UI: New Global Top-Bar (WIP)

== Main Features/Changes for Users

* Add horizontal bar at top of all non-temp windows, consisting out of two horizontal sub-bars.
* Upper sub-bar contains global menus (File, Render, etc.), tabs for workspaces and scene selector.
* Lower sub-bar contains object mode selector, screen-layout and render-layer selector. Later operator and/or tool settings will be placed here.
* Individual sections of the topbar are individually scrollable.
* Workspace tabs can be double- or ctrl-clicked for renaming and contain 'x' icon for deleting.
* Top-bar should scale nicely with DPI.
* The lower half of the top-bar can be hided by dragging the lower top-bar edge up. Better hiding options are planned (e.g. hide in fullscreen modes).
* Info editors at the top of the window and using the full window width with be replaced by the top-bar.
* In fullscreen modes, no more info editor is added on top, the top-bar replaces it.

== Technical Features/Changes

* Adds initial support for global areas

  A global area is part of the window, not part of the regular screen-layout.
  I've added a macro iterator to iterate over both, global and screen-layout level areas. When iterating over areas, from now on developers should always consider if they have to include global areas.
* Adds a TOPBAR editor type

  The editor type is hidden in the UI editor type menu.
* Adds a variation of the ID template to display IDs as tab buttons (template_ID_tabs in BPY)
* Does various changes to RNA button creation code to improve their appearance in the horizontal top-bar.
* Adds support for dynamically sized regions. That is, regions that scale automatically to the layout bounds.

  The code for this is currently a big hack (it's based on drawing the UI multiple times). This should definitely be improved.
* Adds a template for displaying operator properties optimized for the top-bar. This will probably change a lot still and is in fact disabled in code.

Since the final top-bar design depends a lot on other 2.8 designs (mainly tool-system and workspaces), we decided to not show the operator or tool settings in the top-bar for now. That means most of the lower sub-bar is empty for the time being.

NOTE: Top-bar or global area data is not written to files or SDNA. They are simply added to the window when opening Blender or reading a file. This allows us doing changes to the top-bar without having to care for compatibility.

== ToDo's

It's a bit hard to predict all the ToDo's here are the known main ones:
* Add options for the new active-tool system and for operator redo to the topbar.
* Automatically hide the top-bar in fullscreen modes.
* General visual polish.
* Top-bar drag & drop support (WIP in temp-tab_drag_drop).
* Improve dynamic regions (should also fix some layout glitches).
* Make internal terminology consistent.
* Enable topbar file writing once design is more advanced.
* Address TODO's and XXX's in code :)

Thanks @brecht for the review! And @sergey for the complaining ;)

Differential Revision: D2758

68 files changed, 2497 insertions, 593 deletions

diff --git a/build_files/cmake/macros.cmake b/build_files/cmake/macros.cmake
index e581e597fc7..23d4d0d2054 100644
--- a/build_files/cmake/macros.cmake
+++ b/build_files/cmake/macros.cmake
@@ -583,6 +583,7 @@ function(SETUP_BLENDER_SORTED_LIBS)
 		bf_editor_space_sequencer
 		bf_editor_space_text
 		bf_editor_space_time
+		bf_editor_space_topbar
 		bf_editor_space_userpref
 		bf_editor_space_view3d
 		bf_editor_space_clip
diff --git a/release/scripts/startup/bl_ui/__init__.py b/release/scripts/startup/bl_ui/__init__.py
index 5c50cb74fdb..2c0b1ab12be 100644
--- a/release/scripts/startup/bl_ui/__init__.py
+++ b/release/scripts/startup/bl_ui/__init__.py
@@ -84,6 +84,7 @@ _modules = [
     "space_sequencer",
     "space_text",
     "space_time",
+    "space_topbar",
     "space_userpref",
     "space_view3d",
     "space_view3d_toolbar",
diff --git a/release/scripts/startup/bl_ui/space_topbar.py b/release/scripts/startup/bl_ui/space_topbar.py
new file mode 100644
index 00000000000..7ce512ebb2a
--- /dev/null
+++ b/release/scripts/startup/bl_ui/space_topbar.py
@@ -0,0 +1,401 @@
+# ##### BEGIN GPL LICENSE BLOCK #####
+#
+#  This program is free software; you can redistribute it and/or
+#  modify it under the terms of the GNU General Public License
+#  as published by the Free Software Foundation; either version 2
+#  of the License, or (at your option) any later version.
+#
+#  This program is distributed in the hope that it will be useful,
+#  but WITHOUT ANY WARRANTY; without even the implied warranty of
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#  GNU General Public License for more details.
+#
+#  You should have received a copy of the GNU General Public License
+#  along with this program; if not, write to the Free Software Foundation,
+#  Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+#
+# ##### END GPL LICENSE BLOCK #####
+
+# <pep8 compliant>
+import bpy
+from bpy.types import Header, Menu, Panel
+
+
+class TOPBAR_HT_upper_bar(Header):
+    bl_space_type = 'TOPBAR'
+
+    def draw(self, context):
+        region = context.region
+
+        if region.alignment == 'RIGHT':
+            self.draw_right(context)
+        else:
+            self.draw_left(context)
+
+    def draw_left(self, context):
+        layout = self.layout
+
+        window = context.window
+        screen = context.screen
+
+        layout.operator("wm.splash", text="", icon='BLENDER', emboss=False)
+
+        TOPBAR_MT_editor_menus.draw_collapsible(context, layout)
+
+        layout.separator()
+
+        if not screen.show_fullscreen:
+            layout.template_ID_tabs(window, "workspace", new="workspace.workspace_add_menu", unlink="workspace.workspace_delete")
+
+        layout.separator()
+
+        layout.template_running_jobs()
+
+        layout.template_reports_banner()
+
+        row = layout.row(align=True)
+
+        if bpy.app.autoexec_fail is True and bpy.app.autoexec_fail_quiet is False:
+            row.label("Auto-run disabled", icon='ERROR')
+            if bpy.data.is_saved:
+                props = row.operator("wm.revert_mainfile", icon='SCREEN_BACK', text="Reload Trusted")
+                props.use_scripts = True
+
+            row.operator("script.autoexec_warn_clear", text="Ignore")
+
+            # include last so text doesn't push buttons out of the header
+            row.label(bpy.app.autoexec_fail_message)
+            return
+
+    def draw_right(self, context):
+        layout = self.layout
+
+        window = context.window
+
+        layout.template_ID(window, "scene", new="scene.new", unlink="scene.delete")
+
+
+class TOPBAR_HT_lower_bar(Header):
+    bl_space_type = 'TOPBAR'
+    bl_region_type = 'WINDOW'
+
+    def draw(self, context):
+        layout = self.layout
+        region = context.region
+
+        if region.alignment == 'LEFT':
+            self.draw_left(context)
+        elif region.alignment == 'RIGHT':
+            self.draw_right(context)
+        else:
+            # WITH_REDO_REGION_REMOVAL:
+            # layout.template_operator_redo_props()
+            pass
+
+    def draw_left(self, context):
+        layout = self.layout
+        layer = context.view_layer
+
+        act_mode_item = bpy.types.Object.bl_rna.properties['mode'].enum_items[layer.objects.active.mode]
+        layout.operator_menu_enum("object.mode_set", "mode", text=act_mode_item.name, icon=act_mode_item.icon)
+
+
+    def draw_right(self, context):
+        layout = self.layout
+
+        window = context.window
+        workspace = context.workspace
+        scene = context.scene
+        screen = context.screen
+
+        if screen.show_fullscreen:
+            layout.operator("screen.back_to_previous", icon='SCREEN_BACK', text="Back to Previous")
+        else:
+            layout.template_search_preview(window, "screen", workspace, "screens", new="screen.new", unlink="screen.delete", rows=2, cols=6)
+        # Active workspace view-layer is retrieved through window, not through workspace.
+        layout.template_search(window, "view_layer", scene, "view_layers")
+
+
+class TOPBAR_MT_editor_menus(Menu):
+    bl_idname = "TOPBAR_MT_editor_menus"
+    bl_label = ""
+
+    def draw(self, context):
+        self.draw_menus(self.layout, context)
+
+    @staticmethod
+    def draw_menus(layout, context):
+        layout.menu("TOPBAR_MT_file")
+
+        layout.menu("TOPBAR_MT_render")
+
+        layout.menu("TOPBAR_MT_window")
+        layout.menu("TOPBAR_MT_help")
+
+
+class TOPBAR_MT_file(Menu):
+    bl_label = "File"
+
+    def draw(self, context):
+        layout = self.layout
+
+        layout.operator_context = 'INVOKE_AREA'
+        layout.operator("wm.read_homefile", text="New", icon='NEW')
+        layout.operator("wm.open_mainfile", text="Open...", icon='FILE_FOLDER')
+        layout.menu("TOPBAR_MT_file_open_recent", icon='OPEN_RECENT')
+        layout.operator("wm.revert_mainfile", icon='FILE_REFRESH')
+        layout.operator("wm.recover_last_session", icon='RECOVER_LAST')
+        layout.operator("wm.recover_auto_save", text="Recover Auto Save...", icon='RECOVER_AUTO')
+
+        layout.separator()
+
+        layout.operator_context = 'EXEC_AREA' if context.blend_data.is_saved else 'INVOKE_AREA'
+        layout.operator("wm.save_mainfile", text="Save", icon='FILE_TICK')
+
+        layout.operator_context = 'INVOKE_AREA'
+        layout.operator("wm.save_as_mainfile", text="Save As...", icon='SAVE_AS')
+        layout.operator_context = 'INVOKE_AREA'
+        layout.operator("wm.save_as_mainfile", text="Save Copy...", icon='SAVE_COPY').copy = True
+
+        layout.separator()
+
+        layout.operator("screen.userpref_show", text="User Preferences...", icon='PREFERENCES')
+
+        layout.operator_context = 'INVOKE_AREA'
+        layout.operator("wm.save_homefile", icon='SAVE_PREFS')
+        layout.operator("wm.read_factory_settings", icon='LOAD_FACTORY')
+
+        layout.separator()
+
+        layout.operator_context = 'INVOKE_AREA'
+        layout.operator("wm.link", text="Link", icon='LINK_BLEND')
+        layout.operator("wm.append", text="Append", icon='APPEND_BLEND')
+        layout.menu("TOPBAR_MT_file_previews")
+
+        layout.separator()
+
+        layout.menu("TOPBAR_MT_file_import", icon='IMPORT')
+        layout.menu("TOPBAR_MT_file_export", icon='EXPORT')
+
+        layout.separator()
+
+        layout.menu("TOPBAR_MT_file_external_data", icon='EXTERNAL_DATA')
+
+        layout.separator()
+
+        layout.operator_context = 'EXEC_AREA'
+        if bpy.data.is_dirty and context.user_preferences.view.use_quit_dialog:
+            layout.operator_context = 'INVOKE_SCREEN'  # quit dialog
+        layout.operator("wm.quit_blender", text="Quit", icon='QUIT')
+
+
+class TOPBAR_MT_file_import(Menu):
+    bl_idname = "TOPBAR_MT_file_import"
+    bl_label = "Import"
+
+    def draw(self, context):
+        if bpy.app.build_options.collada:
+            self.layout.operator("wm.collada_import", text="Collada (Default) (.dae)")
+        if bpy.app.build_options.alembic:
+            self.layout.operator("wm.alembic_import", text="Alembic (.abc)")
+
+
+class TOPBAR_MT_file_export(Menu):
+    bl_idname = "TOPBAR_MT_file_export"
+    bl_label = "Export"
+
+    def draw(self, context):
+        if bpy.app.build_options.collada:
+            self.layout.operator("wm.collada_export", text="Collada (Default) (.dae)")
+        if bpy.app.build_options.alembic:
+            self.layout.operator("wm.alembic_export", text="Alembic (.abc)")
+
+
+class TOPBAR_MT_file_external_data(Menu):
+    bl_label = "External Data"
+
+    def draw(self, context):
+        layout = self.layout
+
+        icon = 'CHECKBOX_HLT' if bpy.data.use_autopack else 'CHECKBOX_DEHLT'
+        layout.operator("file.autopack_toggle", icon=icon)
+
+        layout.separator()
+
+        pack_all = layout.row()
+        pack_all.operator("file.pack_all")
+        pack_all.active = not bpy.data.use_autopack
+
+        unpack_all = layout.row()
+        unpack_all.operator("file.unpack_all")
+        unpack_all.active = not bpy.data.use_autopack
+
+        layout.separator()
+
+        layout.operator("file.make_paths_relative")
+        layout.operator("file.make_paths_absolute")
+        layout.operator("file.report_missing_files")
+        layout.operator("file.find_missing_files")
+
+
+class TOPBAR_MT_file_previews(Menu):
+    bl_label = "Data Previews"
+
+    def draw(self, context):
+        layout = self.layout
+
+        layout.operator("wm.previews_ensure")
+        layout.operator("wm.previews_batch_generate")
+
+        layout.separator()
+
+        layout.operator("wm.previews_clear")
+        layout.operator("wm.previews_batch_clear")
+
+
+class TOPBAR_MT_game(Menu):
+    bl_label = "Game"
+
+    def draw(self, context):
+        layout = self.layout
+
+        gs = context.scene.game_settings
+
+        layout.operator("view3d.game_start")
+
+        layout.separator()
+
+        layout.prop(gs, "show_debug_properties")
+        layout.prop(gs, "show_framerate_profile")
+        layout.prop(gs, "show_physics_visualization")
+        layout.prop(gs, "use_deprecation_warnings")
+        layout.prop(gs, "use_animation_record")
+        layout.separator()
+        layout.prop(gs, "use_auto_start")
+
+
+class TOPBAR_MT_render(Menu):
+    bl_label = "Render"
+
+    def draw(self, context):
+        layout = self.layout
+
+        layout.operator("render.render", text="Render Image", icon='RENDER_STILL').use_viewport = True
+        props = layout.operator("render.render", text="Render Animation", icon='RENDER_ANIMATION')
+        props.animation = True
+        props.use_viewport = True
+
+        layout.separator()
+
+        layout.operator("render.opengl", text="OpenGL Render Image")
+        layout.operator("render.opengl", text="OpenGL Render Animation").animation = True
+        layout.menu("TOPBAR_MT_opengl_render")
+
+        layout.separator()
+
+        layout.operator("render.view_show")
+        layout.operator("render.play_rendered_anim", icon='PLAY')
+
+
+class TOPBAR_MT_opengl_render(Menu):
+    bl_label = "OpenGL Render Options"
+
+    def draw(self, context):
+        layout = self.layout
+
+        rd = context.scene.render
+        layout.prop(rd, "use_antialiasing")
+        layout.prop(rd, "use_full_sample")
+
+        layout.prop_menu_enum(rd, "antialiasing_samples")
+        layout.prop_menu_enum(rd, "alpha_mode")
+
+
+class TOPBAR_MT_window(Menu):
+    bl_label = "Window"
+
+    def draw(self, context):
+        import sys
+
+        layout = self.layout
+
+        layout.operator("wm.window_new")
+        layout.operator("wm.window_fullscreen_toggle", icon='FULLSCREEN_ENTER')
+
+        layout.separator()
+
+        layout.operator("screen.screenshot")
+        layout.operator("screen.screencast")
+
+        if sys.platform[:3] == "win":
+            layout.separator()
+            layout.operator("wm.console_toggle", icon='CONSOLE')
+
+        if context.scene.render.use_multiview:
+            layout.separator()
+            layout.operator("wm.set_stereo_3d", icon='CAMERA_STEREO')
+
+
+class TOPBAR_MT_help(Menu):
+    bl_label = "Help"
+
+    def draw(self, context):
+        layout = self.layout
+
+        layout.operator(
+                "wm.url_open", text="Manual", icon='HELP',
+                ).url = "https://docs.blender.org/manual/en/dev/"
+        layout.operator(
+                "wm.url_open", text="Release Log", icon='URL',
+                ).url = "http://wiki.blender.org/index.php/Dev:Ref/Release_Notes/%d.%d" % bpy.app.version[:2]
+        layout.separator()
+
+        layout.operator(
+                "wm.url_open", text="Blender Website", icon='URL',
+                ).url = "https://www.blender.org"
+        layout.operator(
+                "wm.url_open", text="Blender Store", icon='URL',
+                ).url = "https://store.blender.org"
+        layout.operator(
+                "wm.url_open", text="Developer Community", icon='URL',
+                ).url = "https://www.blender.org/get-involved/"
+        layout.operator(
+                "wm.url_open", text="User Community", icon='URL',
+                ).url = "https://www.blender.org/support/user-community"
+        layout.separator()
+        layout.operator(
+                "wm.url_open", text="Report a Bug", icon='URL',
+                ).url = "https://developer.blender.org/maniphest/task/edit/form/1"
+        layout.separator()
+
+        layout.operator(
+                "wm.url_open", text="Python API Reference", icon='URL',
+                ).url = bpy.types.WM_OT_doc_view._prefix
+
+        layout.operator("wm.operator_cheat_sheet", icon='TEXT')
+        layout.operator("wm.sysinfo", icon='TEXT')
+        layout.separator()
+
+        layout.operator("wm.splash", icon='BLENDER')
+
+
+classes = (
+    TOPBAR_HT_upper_bar,
+    TOPBAR_HT_lower_bar,
+    TOPBAR_MT_editor_menus,
+    TOPBAR_MT_file,
+    TOPBAR_MT_file_import,
+    TOPBAR_MT_file_export,
+    TOPBAR_MT_file_external_data,
+    TOPBAR_MT_file_previews,
+    TOPBAR_MT_game,
+    TOPBAR_MT_render,
+    TOPBAR_MT_opengl_render,
+    TOPBAR_MT_window,
+    TOPBAR_MT_help,
+)
+
+if __name__ == "__main__":  # only for live edit.
+    from bpy.utils import register_class
+    for cls in classes:
+        register_class(cls)
diff --git a/release/scripts/startup/bl_ui/space_userpref.py b/release/scripts/startup/bl_ui/space_userpref.py
index 953ebba54ca..9afda6b77bf 100644
--- a/release/scripts/startup/bl_ui/space_userpref.py
+++ b/release/scripts/startup/bl_ui/space_userpref.py
@@ -853,6 +853,9 @@ class USERPREF_PT_theme(Panel):
             col.label(text="List Item:")
             self._theme_widget_style(col, ui.wcol_list_item)
 
+            col.label(text="Tab:")
+            self._theme_widget_style(col, ui.wcol_tab)
+
             ui_state = theme.user_interface.wcol_state
             col.label(text="State:")
 
diff --git a/source/blender/blenkernel/BKE_context.h b/source/blender/blenkernel/BKE_context.h
index 8a478a7ae59..6d857c93630 100644
--- a/source/blender/blenkernel/BKE_context.h
+++ b/source/blender/blenkernel/BKE_context.h
@@ -178,6 +178,7 @@ struct SpaceAction *CTX_wm_space_action(const bContext *C);
 struct SpaceInfo *CTX_wm_space_info(const bContext *C);
 struct SpaceUserPref *CTX_wm_space_userpref(const bContext *C);
 struct SpaceClip *CTX_wm_space_clip(const bContext *C);
+struct SpaceTopBar *CTX_wm_space_topbar(const bContext *C);
 
 void CTX_wm_manager_set(bContext *C, struct wmWindowManager *wm);
 void CTX_wm_window_set(bContext *C, struct wmWindow *win);
diff --git a/source/blender/blenkernel/BKE_screen.h b/source/blender/blenkernel/BKE_screen.h
index ee0fb5f2776..2a25120ba8d 100644
--- a/source/blender/blenkernel/BKE_screen.h
+++ b/source/blender/blenkernel/BKE_screen.h
@@ -58,6 +58,7 @@ struct wmWindowManager;
 struct WorkSpace;
 struct GPUFXSettings;
 struct wmMsgBus;
+struct ScrAreaMap;
 
 #include "BLI_compiler_attrs.h"
 
@@ -244,6 +245,7 @@ typedef struct HeaderType {
 
 	char idname[BKE_ST_MAXNAME];        /* unique name */
 	int space_type;
+	int region_type;
 
 	/* draw entirely, view changes should be handled here */
 	void (*draw)(const struct bContext *, struct Header *);
@@ -334,6 +336,7 @@ float BKE_screen_view3d_zoom_from_fac(float zoomfac);
 
 /* screen */
 void BKE_screen_free(struct bScreen *sc); 
+void BKE_screen_area_map_free(struct ScrAreaMap *area_map) ATTR_NONNULL();
 unsigned int BKE_screen_visible_layers(struct bScreen *screen, struct Scene *scene);
 
 struct ScrEdge *BKE_screen_find_edge(struct bScreen *sc, struct ScrVert *v1, struct ScrVert *v2);
diff --git a/source/blender/blenkernel/intern/context.c b/source/blender/blenkernel/intern/context.c
index f5a0d4e7c60..4efd6dee6f6 100644
--- a/source/blender/blenkernel/intern/context.c
+++ b/source/blender/blenkernel/intern/context.c
@@ -831,6 +831,14 @@ struct SpaceClip *CTX_wm_space_clip(const bContext *C)
 	return NULL;
 }
 
+struct SpaceTopBar *CTX_wm_space_topbar(const bContext *C)
+{
+	ScrArea *sa = CTX_wm_area(C);
+	if (sa && sa->spacetype == SPACE_TOPBAR)
+		return sa->spacedata.first;
+	return NULL;
+}
+
 void CTX_wm_manager_set(bContext *C, wmWindowManager *wm)
 {
 	C->wm.manager = wm;
diff --git a/source/blender/blenkernel/intern/screen.c b/source/blender/blenkernel/intern/screen.c
index 8283655503c..77f7b5f847e 100644
--- a/source/blender/blenkernel/intern/screen.c
+++ b/source/blender/blenkernel/intern/screen.c
@@ -397,6 +397,7 @@ void BKE_screen_area_free(ScrArea *sa)
 	for (ar = sa->regionbase.first; ar; ar = ar->next)
 		BKE_area_region_free(st, ar);
 
+	MEM_SAFE_FREE(sa->global);
 	BLI_freelistN(&sa->regionbase);
 	
 	BKE_spacedata_freelist(&sa->spacedata);
@@ -404,10 +405,21 @@ void BKE_screen_area_free(ScrArea *sa)
 	BLI_freelistN(&sa->actionzones);
 }
 
+void BKE_screen_area_map_free(ScrAreaMap *area_map)
+{
+	for (ScrArea *area = area_map->areabase.first, *area_next; area; area = area_next) {
+		area_next = area->next;
+		BKE_screen_area_free(area);
+	}
+
+	BLI_freelistN(&area_map->vertbase);
+	BLI_freelistN(&area_map->edgebase);
+	BLI_freelistN(&area_map->areabase);
+}
+
 /** Free (or release) any data used by this screen (does not free the screen itself). */
 void BKE_screen_free(bScreen *sc)
 {
-	ScrArea *sa, *san;
 	ARegion *ar;
 
 	/* No animdata here. */
@@ -416,18 +428,11 @@ void BKE_screen_free(bScreen *sc)
 		BKE_area_region_free(NULL, ar);
 
 	BLI_freelistN(&sc->regionbase);
-	
-	for (sa = sc->areabase.first; sa; sa = san) {
-		san = sa->next;
-		BKE_screen_area_free(sa);
-	}
-	
-	BLI_freelistN(&sc->vertbase);
-	BLI_freelistN(&sc->edgebase);
-	BLI_freelistN(&sc->areabase);
+
+	BKE_screen_area_map_free(AREAMAP_FROM_SCREEN(sc));
 
 	BKE_previewimg_free(&sc->preview);
-	
+
 	/* Region and timer are freed by the window manager. */
 	MEM_SAFE_FREE(sc->tool_tip);
 }
diff --git a/source/blender/blenloader/intern/readblenentry.c b/source/blender/blenloader/intern/readblenentry.c
index 73109413271..8d90a11f5d9 100644
--- a/source/blender/blenloader/intern/readblenentry.c
+++ b/source/blender/blenloader/intern/readblenentry.c
@@ -282,7 +282,7 @@ LinkNode *BLO_blendhandle_get_linkable_groups(BlendHandle *bh)
 		else if (BKE_idcode_is_valid(bhead->code)) {
 			if (BKE_idcode_is_linkable(bhead->code)) {
 				const char *str = BKE_idcode_to_name(bhead->code);
-				
+
 				if (BLI_gset_add(gathered, (void *)str)) {
 					BLI_linklist_prepend(&names, strdup(str));
 				}
diff --git a/source/blender/blenloader/intern/readfile.c b/source/blender/blenloader/intern/readfile.c
index 5dc98964fbd..b9f9fc638cc 100644
--- a/source/blender/blenloader/intern/readfile.c
+++ b/source/blender/blenloader/intern/readfile.c
@@ -6396,6 +6396,8 @@ static void direct_link_area(FileData *fd, ScrArea *area)
 	area->type = NULL;	/* spacetype callbacks */
 	area->region_active_win = -1;
 
+	area->global = newdataadr(fd, area->global);
+
 	/* if we do not have the spacetype registered we cannot
 	 * free it, so don't allocate any new memory for such spacetypes. */
 	if (!BKE_spacetype_exists(area->spacetype)) {
@@ -6630,9 +6632,9 @@ static void direct_link_area(FileData *fd, ScrArea *area)
 	area->v4 = newdataadr(fd, area->v4);
 }
 
-static void lib_link_area(FileData *fd, bScreen *sc, ScrArea *area)
+static void lib_link_area(FileData *fd, ID *parent_id, ScrArea *area)
 {
-	area->full = newlibadr(fd, sc->id.lib, area->full);
+	area->full = newlibadr(fd, parent_id->lib, area->full);
 
 	for (SpaceLink *sl = area->spacedata.first; sl; sl= sl->next) {
 		switch (sl->spacetype) {
@@ -6640,11 +6642,11 @@ static void lib_link_area(FileData *fd, bScreen *sc, ScrArea *area)
 			{
 				View3D *v3d = (View3D*) sl;
 
-				v3d->camera= newlibadr(fd, sc->id.lib, v3d->camera);
-				v3d->ob_centre= newlibadr(fd, sc->id.lib, v3d->ob_centre);
+				v3d->camera= newlibadr(fd, parent_id->lib, v3d->camera);
+				v3d->ob_centre= newlibadr(fd, parent_id->lib, v3d->ob_centre);
 
 				if (v3d->localvd) {
-					v3d->localvd->camera = newlibadr(fd, sc->id.lib, v3d->localvd->camera);
+					v3d->localvd->camera = newlibadr(fd, parent_id->lib, v3d->localvd->camera);
 				}
 				break;
 			}
@@ -6654,15 +6656,15 @@ static void lib_link_area(FileData *fd, bScreen *sc, ScrArea *area)
 				bDopeSheet *ads = sipo->ads;
 
 				if (ads) {
-					ads->source = newlibadr(fd, sc->id.lib, ads->source);
-					ads->filter_grp = newlibadr(fd, sc->id.lib, ads->filter_grp);
+					ads->source = newlibadr(fd, parent_id->lib, ads->source);
+					ads->filter_grp = newlibadr(fd, parent_id->lib, ads->filter_grp);
 				}
 				break;
 			}
 			case SPACE_BUTS:
 			{
 				SpaceButs *sbuts = (SpaceButs *)sl;
-				sbuts->pinid = newlibadr(fd, sc->id.lib, sbuts->pinid);
+				sbuts->pinid = newlibadr(fd, parent_id->lib, sbuts->pinid);
 				if (sbuts->pinid == NULL) {
 					sbuts->flag &= ~SB_PIN_CONTEXT;
 				}
@@ -6676,24 +6678,24 @@ static void lib_link_area(FileData *fd, bScreen *sc, ScrArea *area)
 				bDopeSheet *ads = &saction->ads;
 
 				if (ads) {
-					ads->source = newlibadr(fd, sc->id.lib, ads->source);
-					ads->filter_grp = newlibadr(fd, sc->id.lib, ads->filter_grp);
+					ads->source = newlibadr(fd, parent_id->lib, ads->source);
+					ads->filter_grp = newlibadr(fd, parent_id->lib, ads->filter_grp);
 				}
 
-				saction->action = newlibadr(fd, sc->id.lib, saction->action);
+				saction->action = newlibadr(fd, parent_id->lib, saction->action);
 				break;
 			}
 			case SPACE_IMAGE:
 			{
 				SpaceImage *sima = (SpaceImage *)sl;
 
-				sima->image = newlibadr_real_us(fd, sc->id.lib, sima->image);
-				sima->mask_info.mask = newlibadr_real_us(fd, sc->id.lib, sima->mask_info.mask);
+				sima->image = newlibadr_real_us(fd, parent_id->lib, sima->image);
+				sima->mask_info.mask = newlibadr_real_us(fd, parent_id->lib, sima->mask_info.mask);
 
 				/* NOTE: pre-2.5, this was local data not lib data, but now we need this as lib data
 				 * so fingers crossed this works fine!
 				 */
-				sima->gpd = newlibadr_us(fd, sc->id.lib, sima->gpd);
+				sima->gpd = newlibadr_us(fd, parent_id->lib, sima->gpd);
 				break;
 			}
 			case SPACE_SEQ:
@@ -6703,7 +6705,7 @@ static void lib_link_area(FileData *fd, bScreen *sc, ScrArea *area)
 				/* NOTE: pre-2.5, this was local data not lib data, but now we need this as lib data
 				 * so fingers crossed this works fine!
 				 */
-				sseq->gpd = newlibadr_us(fd, sc->id.lib, sseq->gpd);
+				sseq->gpd = newlibadr_us(fd, parent_id->lib, sseq->gpd);
 				break;
 			}
 			case SPACE_NLA:
@@ -6712,8 +6714,8 @@ static void lib_link_area(FileData *fd, bScreen *sc, ScrArea *area)
 				bDopeSheet *ads= snla->ads;
 
 				if (ads) {
-					ads->source = newlibadr(fd, sc->id.lib, ads->source);
-					ads->filter_grp = newlibadr(fd, sc->id.lib, ads->filter_grp);
+					ads->source = newlibadr(fd, parent_id->lib, ads->source);
+					ads->filter_grp = newlibadr(fd, parent_id->lib, ads->filter_grp);
 				}
 				break;
 			}
@@ -6721,7 +6723,7 @@ static void lib_link_area(FileData *fd, bScreen *sc, ScrArea *area)
 			{
 				SpaceText *st= (SpaceText *)sl;
 
-				st->text= newlibadr(fd, sc->id.lib, st->text);
+				st->text= newlibadr(fd, parent_id->lib, st->text);
 				break;
 			}
 			case SPACE_SCRIPT:
@@ -6729,7 +6731,7 @@ static void lib_link_area(FileData *fd, bScreen *sc, ScrArea *area)
 				SpaceScript *scpt = (SpaceScript *)sl;
 				/*scpt->script = NULL; - 2.45 set to null, better re-run the script */
 				if (scpt->script) {
-					scpt->script = newlibadr(fd, sc->id.lib, scpt->script);
+					scpt->script = newlibadr(fd, parent_id->lib, scpt->script);
 					if (scpt->script) {
 						SCRIPT_SET_NULL(scpt->script);
 					}
@@ -6763,11 +6765,11 @@ static void lib_link_area(FileData *fd, bScreen *sc, ScrArea *area)
 				bNodeTree *ntree;
 
 				/* node tree can be stored locally in id too, link this first */
-				snode->id = newlibadr(fd, sc->id.lib, snode->id);
-				snode->from = newlibadr(fd, sc->id.lib, snode->from);
+				snode->id = newlibadr(fd, parent_id->lib, snode->id);
+				snode->from = newlibadr(fd, parent_id->lib, snode->from);
 
 				ntree = snode->id ? ntreeFromID(snode->id) : NULL;
-				snode->nodetree = ntree ? ntree : newlibadr_us(fd, sc->id.lib, snode->nodetree);
+				snode->nodetree = ntree ? ntree : newlibadr_us(fd, parent_id->lib, snode->nodetree);
 
 				for (path = snode->treepath.first; path; path = path->next) {
 					if (path == snode->treepath.first) {
@@ -6775,7 +6777,7 @@ static void lib_link_area(FileData *fd, bScreen *sc, ScrArea *area)
 						path->nodetree = snode->nodetree;
 					}
 					else
-						path->nodetree = newlibadr_us(fd, sc->id.lib, path->nodetree);
+						path->nodetree = newlibadr_us(fd, parent_id->lib, path->nodetree);
 
 					if (!path->nodetree)
 						break;
@@ -6803,9 +6805,8 @@ static void lib_link_area(FileData *fd, bScreen *sc, ScrArea *area)
 			case SPACE_CLIP:
 			{
 				SpaceClip *sclip = (SpaceClip *)sl;
-
-				sclip->clip = newlibadr_real_us(fd, sc->id.lib, sclip->clip);
-				sclip->mask_info.mask = newlibadr_real_us(fd, sc->id.lib, sclip->mask_info.mask);
+				sclip->clip = newlibadr_real_us(fd, parent_id->lib, sclip->clip);
+				sclip->mask_info.mask = newlibadr_real_us(fd, parent_id->lib, sclip->mask_info.mask);
 				break;
 			}
 			default:
@@ -6814,6 +6815,34 @@ static void lib_link_area(FileData *fd, bScreen *sc, ScrArea *area)
 	}
 }
 
+/**
+ * \return false on error.
+ */
+static bool direct_link_area_map(FileData *fd, ScrAreaMap *area_map)
+{
+	link_list(fd, &area_map->vertbase);
+	link_list(fd, &area_map->edgebase);
+	link_list(fd, &area_map->areabase);
+	for (ScrArea *area = area_map->areabase.first; area; area = area->next) {
+		direct_link_area(fd, area);
+	}
+
+	/* edges */
+	for (ScrEdge *se = area_map->edgebase.first; se; se = se->next) {
+		se->v1 = newdataadr(fd, se->v1);
+		se->v2 = newdataadr(fd, se->v2);
+		BKE_screen_sort_scrvert(&se->v1, &se->v2);
+
+		if (se->v1 == NULL) {
+			BLI_remlink(&area_map->edgebase, se);
+
+			return false;
+		}
+	}
+
+	return true;
+}
+
 /* ************ READ WM ***************** */
 
 static void direct_link_windowmanager(FileData *fd, wmWindowManager *wm)
@@ -6830,6 +6859,8 @@ static void direct_link_windowmanager(FileData *fd, wmWindowManager *wm)
 		/* we need to restore a pointer to this later when reading workspaces, so store in global oldnew-map */
 		oldnewmap_insert(fd->globmap, hook, win->workspace_hook, 0);
 
+		direct_link_area_map(fd, &win->global_areas);
+
 		win->ghostwin = NULL;
 		win->gwnctx = NULL;
 		win->eventstate = NULL;
@@ -6901,6 +6932,10 @@ static void lib_link_windowmanager(FileData *fd, Main *main)
 				win->scene = newlibadr(fd, wm->id.lib, win->scene);
 				/* deprecated, but needed for versioning (will be NULL'ed then) */
 				win->screen = newlibadr(fd, NULL, win->screen);
+	
+				for (ScrArea *area = win->global_areas.areabase.first; area; area = area->next) {
+					lib_link_area(fd, &wm->id, area);
+				}
 			}
 
 			wm->id.tag &= ~LIB_TAG_NEED_LINK;
@@ -6927,7 +6962,7 @@ static void lib_link_screen(FileData *fd, Main *main)
 			sc->scrubbing = false;
 			
 			for (ScrArea *area = sc->areabase.first; area; area = area->next) {
-				lib_link_area(fd, sc, area);
+				lib_link_area(fd, &sc->id, area);
 			}
 			sc->id.tag &= ~LIB_TAG_NEED_LINK;
 		}
@@ -7353,14 +7388,8 @@ void blo_do_versions_view3d_split_250(View3D *v3d, ListBase *regions)
 
 static bool direct_link_screen(FileData *fd, bScreen *sc)
 {
-	ScrArea *sa;
-	ScrVert *sv;
-	ScrEdge *se;
 	bool wrong_id = false;
 	
-	link_list(fd, &(sc->vertbase));
-	link_list(fd, &(sc->edgebase));
-	link_list(fd, &(sc->areabase));
 	sc->regionbase.first = sc->regionbase.last= NULL;
 	sc->context = NULL;
 	sc->active_region = NULL;
@@ -7368,28 +7397,11 @@ static bool direct_link_screen(FileData *fd, bScreen *sc)
 
 	sc->preview = direct_link_preview_image(fd, sc->preview);
 
-	/* edges */
-	for (se = sc->edgebase.first; se; se = se->next) {
-		se->v1 = newdataadr(fd, se->v1);
-		se->v2 = newdataadr(fd, se->v2);
-		if ((intptr_t)se->v1 > (intptr_t)se->v2) {
-			sv = se->v1;
-			se->v1 = se->v2;
-			se->v2 = sv;
-		}
-		
-		if (se->v1 == NULL) {
-			printf("Error reading Screen %s... removing it.\n", sc->id.name+2);
-			BLI_remlink(&sc->edgebase, se);
-			wrong_id = true;
-		}
+	if (!direct_link_area_map(fd, AREAMAP_FROM_SCREEN(sc))) {
+		printf("Error reading Screen %s... removing it.\n", sc->id.name + 2);
+		wrong_id = true;
 	}
-	
-	/* areas */
-	for (sa = sc->areabase.first; sa; sa = sa->next) {
-		direct_link_area(fd, sa);
-	}
-	
+
 	return wrong_id;
 }
 
diff --git a/source/blender/blenloader/intern/versioning_280.c b/source/blender/blenloader/intern/versioning_280.c
index 493bf17a552..18eff782d99 100644
--- a/source/blender/blenloader/intern/versioning_280.c
+++ b/source/blender/blenloader/intern/versioning_280.c
@@ -65,6 +65,7 @@
 #include "BKE_node.h"
 #include "BKE_report.h"
 #include "BKE_scene.h"
+#include "BKE_screen.h"
 #include "BKE_workspace.h"
 
 #include "BLO_readfile.h"
@@ -945,4 +946,60 @@ void blo_do_versions_280(FileData *fd, Library *UNUSED(lib), Main *main)
 			}
 		}
 	}
+
+	if (!DNA_struct_find(fd->filesdna, "SpaceTopBar")) {
+		/* Remove info editor, but only if at the top of the window. */
+		for (bScreen *screen = main->screen.first; screen; screen = screen->id.next) {
+			/* Calculate window width/height from screen vertices */
+			int win_width = 0, win_height = 0;
+			for (ScrVert *vert = screen->vertbase.first; vert; vert = vert->next) {
+				win_width  = MAX2(win_width, vert->vec.x);
+				win_height = MAX2(win_height, vert->vec.y);
+			}
+
+			for (ScrArea *area = screen->areabase.first, *area_next; area; area = area_next) {
+				area_next = area->next;
+
+				if (area->spacetype == SPACE_INFO) {
+					if ((area->v2->vec.y == win_height) && (area->v1->vec.x == 0) && (area->v4->vec.x == win_width)) {
+						BKE_screen_area_free(area);
+
+						BLI_remlink(&screen->areabase, area);
+
+						BKE_screen_remove_double_scredges(screen);
+						BKE_screen_remove_unused_scredges(screen);
+						BKE_screen_remove_unused_scrverts(screen);
+
+						MEM_freeN(area);
+					}
+				}
+				/* AREA_TEMP_INFO is deprecated from now on, it should only be set for info areas
+				 * which are deleted above, so don't need to unset it. Its slot/bit can be reused */
+			}
+		}
+	}
+
+#ifdef WITH_REDO_REGION_REMOVAL
+	if (!MAIN_VERSION_ATLEAST(main, 280, TO_BE_DETERMINED)) {
+		/* Remove tool property regions. */
+		for (bScreen *screen = main->screen.first; screen; screen = screen->id.next) {
+			for (ScrArea *sa = screen->areabase.first; sa; sa = sa->next) {
+				for (SpaceLink *sl = sa->spacedata.first; sl; sl = sl->next) {
+					if (ELEM(sl->spacetype, SPACE_VIEW3D, SPACE_CLIP)) {
+						ListBase *regionbase = (sl == sa->spacedata.first) ? &sa->regionbase : &sl->regionbase;
+
+						for (ARegion *region = regionbase->first, *region_next; region; region = region_next) {
+							region_next = region->next;
+
+							if (region->regiontype == RGN_TYPE_TOOL_PROPS) {
+								BKE_area_region_free(NULL, region);
+								BLI_freelinkN(regionbase, region);
+							}
+						}
+					}
+				}
+			}
+		}
+	}
+#endif
 }
diff --git a/source/blender/blenloader/intern/writefile.c b/source/blender/blenloader/intern/writefile.c
index d137510b510..ea6a18b2b48 100644
--- a/source/blender/blenloader/intern/writefile.c
+++ b/source/blender/blenloader/intern/writefile.c
@@ -2878,8 +2878,12 @@ static void write_area_regions(WriteData *wd, ScrArea *area)
 				writedata(wd, DATA, cl->len + 1, cl->line);
 			}
 			writestruct(wd, DATA, SpaceConsole, 1, sl);
-
 		}
+#ifdef WITH_TOPBAR_WRITING
+		else if (sl->spacetype == SPACE_TOPBAR) {
+			writestruct(wd, DATA, SpaceTopBar, 1, sl);
+		}
+#endif
 		else if (sl->spacetype == SPACE_USERPREF) {
 			writestruct(wd, DATA, SpaceUserPref, 1, sl);
 		}
@@ -2890,7 +2894,21 @@ static void write_area_regions(WriteData *wd, ScrArea *area)
 			writestruct(wd, DATA, SpaceInfo, 1, sl);
 		}
 	}
+}
+
+static void write_area_map(WriteData *wd, ScrAreaMap *area_map)
+{
+	writelist(wd, DATA, ScrVert, &area_map->vertbase);
+	writelist(wd, DATA, ScrEdge, &area_map->edgebase);
+	for (ScrArea *area = area_map->areabase.first; area; area = area->next) {
+		writestruct(wd, DATA, ScrArea, 1, area);
+
+#ifdef WITH_TOPBAR_WRITING
+		writestruct(wd, DATA, ScrGlobalAreaData, 1, area->global);
+#endif
 
+		write_area_regions(wd, area);
+	}
 }
 
 static void write_windowmanager(WriteData *wd, wmWindowManager *wm)
@@ -2899,6 +2917,11 @@ static void write_windowmanager(WriteData *wd, wmWindowManager *wm)
 	write_iddata(wd, &wm->id);
 
 	for (wmWindow *win = wm->windows.first; win; win = win->next) {
+#ifndef WITH_TOPBAR_WRITING
+		/* Don't write global areas yet, while we make changes to them. */
+		ScrAreaMap global_areas = win->global_areas;
+		memset(&win->global_areas, 0, sizeof(win->global_areas));
+#endif
 
 		/* update deprecated screen member (for so loading in 2.7x uses the correct screen) */
 		win->screen = BKE_workspace_active_screen_get(win->workspace_hook);
@@ -2907,6 +2930,12 @@ static void write_windowmanager(WriteData *wd, wmWindowManager *wm)
 		writestruct(wd, DATA, WorkSpaceInstanceHook, 1, win->workspace_hook);
 		writestruct(wd, DATA, Stereo3dFormat, 1, win->stereo3d_format);
 
+#ifdef WITH_TOPBAR_WRITING
+		write_area_map(wd, &win->global_areas);
+#else
+		win->global_areas = global_areas;
+#endif
+
 		/* data is written, clear deprecated data again */
 		win->screen = NULL;
 	}
@@ -2922,19 +2951,7 @@ static void write_screen(WriteData *wd, bScreen *sc)
 	write_previews(wd, sc->preview);
 
 	/* direct data */
-	for (ScrVert *sv = sc->vertbase.first; sv; sv = sv->next) {
-		writestruct(wd, DATA, ScrVert, 1, sv);
-	}
-
-	for (ScrEdge *se = sc->edgebase.first; se; se = se->next) {
-		writestruct(wd, DATA, ScrEdge, 1, se);
-	}
-
-	for (ScrArea *sa = sc->areabase.first; sa; sa = sa->next) {
-		writestruct(wd, DATA, ScrArea, 1, sa);
-
-		write_area_regions(wd, sa);
-	}
+	write_area_map(wd, AREAMAP_FROM_SCREEN(sc));
 }
 
 static void write_bone(WriteData *wd, Bone *bone)
diff --git a/source/blender/editors/CMakeLists.txt b/source/blender/editors/CMakeLists.txt
index 619b031e27a..f6ceda9bc5a 100644
--- a/source/blender/editors/CMakeLists.txt
+++ b/source/blender/editors/CMakeLists.txt
@@ -56,6 +56,7 @@ if(WITH_BLENDER)
 	add_subdirectory(space_sequencer)
 	add_subdirectory(space_text)
 	add_subdirectory(space_time)
+	add_subdirectory(space_topbar)
 	add_subdirectory(space_userpref)
 	add_subdirectory(space_view3d)
 	add_subdirectory(transform)
diff --git a/source/blender/editors/gpencil/gpencil_convert.c b/source/blender/editors/gpencil/gpencil_convert.c
index 2c3c9f4f9b9..19663b66f92 100644
--- a/source/blender/editors/gpencil/gpencil_convert.c
+++ b/source/blender/editors/gpencil/gpencil_convert.c
@@ -1450,7 +1450,7 @@ static void gp_convert_ui(bContext *C, wmOperator *op)
 	RNA_pointer_create(&wm->id, op->type->srna, op->properties, &ptr);
 	
 	/* Main auto-draw call */
-	uiDefAutoButsRNA(layout, &ptr, gp_convert_draw_check_prop, '\0');
+	uiDefAutoButsRNA(layout, &ptr, gp_convert_draw_check_prop, UI_BUT_LABEL_ALIGN_NONE, false);
 }
 
 void GPENCIL_OT_convert(wmOperatorType *ot)
diff --git a/source/blender/editors/include/ED_screen.h b/source/blender/editors/include/ED_screen.h
index 0a1ddabb294..8d7b6c86aa1 100644
--- a/source/blender/editors/include/ED_screen.h
+++ b/source/blender/editors/include/ED_screen.h
@@ -111,6 +111,11 @@ int     ED_area_header_switchbutton(const struct bContext *C, struct uiBlock *bl
 void    ED_area_initialize(struct wmWindowManager *wm, struct wmWindow *win, struct ScrArea *sa);
 void    ED_area_exit(struct bContext *C, struct ScrArea *sa);
 int     ED_screen_area_active(const struct bContext *C);
+void    ED_screen_global_topbar_area_create(
+            struct wmWindow *win,
+            const struct bScreen *screen);
+void    ED_screen_global_areas_create(
+            struct wmWindow *win);
 void    ED_area_do_listen(struct bScreen *sc, ScrArea *sa, struct wmNotifier *note, Scene *scene,
                           struct WorkSpace *workspace);
 void    ED_area_tag_redraw(ScrArea *sa);
@@ -123,6 +128,23 @@ void    ED_area_newspace(struct bContext *C, ScrArea *sa, int type, const bool s
 void    ED_area_prevspace(struct bContext *C, ScrArea *sa);
 void    ED_area_swapspace(struct bContext *C, ScrArea *sa1, ScrArea *sa2);
 int     ED_area_headersize(void);
+int     ED_area_global_size_y(const ScrArea *area);
+bool    ED_area_is_global(const ScrArea *area);
+int     ED_region_global_size_y(void);
+
+/** Iterate over all areas visible in the screen (screen as in everything visible in the window, not just bScreen) */
+#define ED_screen_areas_iter(win, screen, area_name)                       \
+	for (ScrArea *area_name = (win)->global_areas.areabase.first ?         \
+	                                  (win)->global_areas.areabase.first : \
+	                                  screen->areabase.first;              \
+	     area_name != NULL;                                                \
+	     area_name = (area_name == (win)->global_areas.areabase.last) ? (screen)->areabase.first : area_name->next)
+#define ED_screen_verts_iter(win, screen, vert_name)                       \
+	for (ScrVert *vert_name = (win)->global_areas.vertbase.first ?         \
+	                                  (win)->global_areas.vertbase.first : \
+	                                  screen->vertbase.first;              \
+	     vert_name != NULL;                                                \
+	     vert_name = (vert_name == (win)->global_areas.vertbase.last) ? (screen)->vertbase.first : vert_name->next)
 
 /* screens */
 void    ED_screens_initialize(struct wmWindowManager *wm);
@@ -130,6 +152,7 @@ void    ED_screen_draw_edges(struct wmWindow *win);
 void    ED_screen_draw_join_shape(struct ScrArea *sa1, struct ScrArea *sa2);
 void    ED_screen_draw_split_preview(struct ScrArea *sa, const int dir, const float fac);
 void    ED_screen_refresh(struct wmWindowManager *wm, struct wmWindow *win);
+void    ED_screen_ensure_updated(struct wmWindowManager *wm, struct wmWindow *win, struct bScreen *screen);
 void    ED_screen_do_listen(struct bContext *C, struct wmNotifier *note);
 bool    ED_screen_change(struct bContext *C, struct bScreen *sc);
 void    ED_screen_update_after_scene_change(
diff --git a/source/blender/editors/include/ED_space_api.h b/source/blender/editors/include/ED_space_api.h
index d268c578cf2..873ab8371fc 100644
--- a/source/blender/editors/include/ED_space_api.h
+++ b/source/blender/editors/include/ED_space_api.h
@@ -58,6 +58,7 @@ void ED_spacetype_logic(void);
 void ED_spacetype_console(void);
 void ED_spacetype_userpref(void);
 void ED_spacetype_clip(void);
+void ED_spacetype_topbar(void);
 
 /* calls for instancing and freeing spacetype static data 
  * called in WM_init_exit */
diff --git a/source/blender/editors/include/ED_undo.h b/source/blender/editors/include/ED_undo.h
index 43ffb091666..da8cd95555c 100644
--- a/source/blender/editors/include/ED_undo.h
+++ b/source/blender/editors/include/ED_undo.h
@@ -25,6 +25,8 @@
 #ifndef __ED_UNDO_H__
 #define __ED_UNDO_H__
 
+#include "BLI_compiler_attrs.h"
+
 struct bContext;
 struct CLG_LogRef;
 struct wmOperator;
@@ -50,6 +52,16 @@ int     ED_undo_operator_repeat(struct bContext *C, struct wmOperator *op);
 void    ED_undo_operator_repeat_cb(struct bContext *C, void *arg_op, void *arg_unused);
 void    ED_undo_operator_repeat_cb_evt(struct bContext *C, void *arg_op, int arg_unused);
 
+#ifdef WITH_REDO_REGION_REMOVAL
+/* Context sanity helpers for operator repeat. */
+typedef struct OperatorRepeatContextHandle OperatorRepeatContextHandle;
+
+const OperatorRepeatContextHandle *ED_operator_repeat_prepare_context(
+        struct bContext *C, struct wmOperator *op) ATTR_WARN_UNUSED_RESULT;
+void ED_operator_repeat_reset_context(
+        struct bContext *C, const OperatorRepeatContextHandle *context_info);
+#endif
+
 bool    ED_undo_is_valid(const struct bContext *C, const char *undoname);
 
 struct UndoStack *ED_undo_stack_get(void);
diff --git a/source/blender/editors/include/ED_util.h b/source/blender/editors/include/ED_util.h
index 2653585dacc..69e80f60d0a 100644
--- a/source/blender/editors/include/ED_util.h
+++ b/source/blender/editors/include/ED_util.h
@@ -31,11 +31,10 @@
 #ifndef __ED_UTIL_H__
 #define __ED_UTIL_H__
 
+#include "BLI_compiler_attrs.h"
+
 struct bContext;
 struct wmOperatorType;
-struct ScrArea;
-struct SpaceLink;
-struct PackedFile;
 
 /* ed_util.c */
 
diff --git a/source/blender/editors/include/UI_interface.h b/source/blender/editors/include/UI_interface.h
index d85c77d55fb..402be964436 100644
--- a/source/blender/editors/include/UI_interface.h
+++ b/source/blender/editors/include/UI_interface.h
@@ -699,8 +699,30 @@ uiBut *uiDefSearchButO_ptr(uiBlock *block, struct wmOperatorType *ot, struct IDP
                            void *arg, int retval, int icon, int maxlen, int x, int y,
                            short width, short height, float a1, float a2, const char *tip);
 
+
+/* For uiDefAutoButsRNA */
+typedef enum {
+	/* Keep current layout for aligning label with property button. */
+	UI_BUT_LABEL_ALIGN_NONE,
+	/* Align label and property button vertically. */
+	UI_BUT_LABEL_ALIGN_COLUMN,
+	/* Split layout into a column for the label and one for property button. */
+	UI_BUT_LABEL_ALIGN_SPLIT_COLUMN,
+} eButLabelAlign;
+
+/* Return info for uiDefAutoButsRNA */
+typedef enum {
+	/* Returns when no buttons were added */
+	UI_PROP_BUTS_NONE_ADDED       = (1 << 0),
+	/* Returned when any property failed the custom check callback (check_prop) */
+	UI_PROP_BUTS_ANY_FAILED_CHECK = (1 << 1),
+} eAutoPropButsReturn;
+
 uiBut *uiDefAutoButR(uiBlock *block, struct PointerRNA *ptr, struct PropertyRNA *prop, int index, const char *name, int icon, int x1, int y1, int x2, int y2);
-int uiDefAutoButsRNA(uiLayout *layout, struct PointerRNA *ptr, bool (*check_prop)(struct PointerRNA *, struct PropertyRNA *), const char label_align);
+eAutoPropButsReturn uiDefAutoButsRNA(
+        uiLayout *layout, struct PointerRNA *ptr,
+        bool (*check_prop)(struct PointerRNA *, struct PropertyRNA *),
+        eButLabelAlign label_align, const bool compact);
 
 /* use inside searchfunc to add items */
 bool    UI_search_item_add(uiSearchItems *items, const char *name, void *poin, int iconid);
@@ -836,6 +858,7 @@ void UI_exit(void);
 #define UI_LAYOUT_ALIGN_CENTER  2
 #define UI_LAYOUT_ALIGN_RIGHT   3
 
+#define UI_ITEM_O_RETURN_PROPS  (1 << 0)
 #define UI_ITEM_R_EXPAND        (1 << 1)
 #define UI_ITEM_R_SLIDER        (1 << 2)
 #define UI_ITEM_R_TOGGLE        (1 << 3)
@@ -845,10 +868,15 @@ void UI_exit(void);
 #define UI_ITEM_R_NO_BG         (1 << 7)
 #define UI_ITEM_R_IMMEDIATE     (1 << 8)
 #define UI_ITEM_O_DEPRESS       (1 << 9)
+#define UI_ITEM_R_COMPACT       (1 << 10)
 
-/* uiTemplateOperatorPropertyButs flags */
-#define UI_TEMPLATE_OP_PROPS_SHOW_TITLE 1
-#define UI_TEMPLATE_OP_PROPS_SHOW_EMPTY 2
+
+/* uiLayoutOperatorButs flags */
+enum {
+	UI_TEMPLATE_OP_PROPS_SHOW_TITLE       = (1 << 0),
+	UI_TEMPLATE_OP_PROPS_SHOW_EMPTY       = (1 << 1),
+	UI_TEMPLATE_OP_PROPS_COMPACT          = (1 << 2),
+};
 
 /* used for transp checkers */
 #define UI_ALPHA_CHECKER_DARK 100
@@ -931,6 +959,11 @@ void uiTemplateIDBrowse(
 void uiTemplateIDPreview(
         uiLayout *layout, struct bContext *C, struct PointerRNA *ptr, const char *propname,
         const char *newop, const char *openop, const char *unlinkop, int rows, int cols, int filter);
+void uiTemplateIDTabs(
+        uiLayout *layout, struct bContext *C,
+        PointerRNA *ptr, const char *propname,
+        const char *newop, const char *openop, const char *unlinkop,
+        int filter);
 void uiTemplateAnyID(uiLayout *layout, struct PointerRNA *ptr, const char *propname, 
                      const char *proptypename, const char *text);
 void uiTemplateSearch(
@@ -947,6 +980,9 @@ void uiTemplateSearchPreview(
 void uiTemplatePathBuilder(uiLayout *layout, struct PointerRNA *ptr, const char *propname, 
                            struct PointerRNA *root_ptr, const char *text);
 uiLayout *uiTemplateModifier(uiLayout *layout, struct bContext *C, struct PointerRNA *ptr);
+#ifdef WITH_REDO_REGION_REMOVAL
+void uiTemplateOperatorRedoProperties(uiLayout *layout, struct bContext *C);
+#endif
 uiLayout *uiTemplateConstraint(uiLayout *layout, struct PointerRNA *ptr);
 void uiTemplatePreview(uiLayout *layout, struct bContext *C, struct ID *id, int show_buttons, struct ID *parent,
                        struct MTex *slot, const char *preview_id);
@@ -971,9 +1007,10 @@ void uiTemplateImageInfo(uiLayout *layout, struct bContext *C, struct Image *ima
 void uiTemplateRunningJobs(uiLayout *layout, struct bContext *C);
 void UI_but_func_operator_search(uiBut *but);
 void uiTemplateOperatorSearch(uiLayout *layout);
-void uiTemplateOperatorPropertyButs(const struct bContext *C, uiLayout *layout, struct wmOperator *op,
-                                    bool (*check_prop)(struct PointerRNA *, struct PropertyRNA *),
-                                    const char label_align, const short flag);
+eAutoPropButsReturn uiTemplateOperatorPropertyButs(
+        const struct bContext *C, uiLayout *layout, struct wmOperator *op,
+        bool (*check_prop)(struct PointerRNA *, struct PropertyRNA *),
+        const eButLabelAlign label_align, const short flag);
 void uiTemplateHeader3D(uiLayout *layout, struct bContext *C);
 void uiTemplateEditModeSelection(uiLayout *layout, struct bContext *C);
 void uiTemplateReportsBanner(uiLayout *layout, struct bContext *C);
diff --git a/source/blender/editors/include/UI_resources.h b/source/blender/editors/include/UI_resources.h
index 7d2837ffe4e..49c9cffdd54 100644
--- a/source/blender/editors/include/UI_resources.h
+++ b/source/blender/editors/include/UI_resources.h
@@ -51,7 +51,7 @@ typedef enum {
 /* use to denote intentionally unset theme color */
 #define TH_UNDEFINED -1
 
-enum {
+typedef enum ThemeColorID {
 	TH_REDALERT,
 
 	TH_THEMEUI,
@@ -308,7 +308,7 @@ enum {
 
 	TH_EDGE_BEVEL,
 	TH_VERTEX_BEVEL
-};
+} ThemeColorID;
 
 /* specific defines per space should have higher define values */
 
diff --git a/source/blender/editors/interface/interface.c b/source/blender/editors/interface/interface.c
index 20eb0ce50e5..a9fdd1678e2 100644
--- a/source/blender/editors/interface/interface.c
+++ b/source/blender/editors/interface/interface.c
@@ -1193,7 +1193,7 @@ void UI_block_end_ex(const bContext *C, uiBlock *block, const int xy[2], int r_x
 	if (block->layouts.first) {
 		UI_block_layout_resolve(block, NULL, NULL);
 	}
-	ui_block_align_calc(block);
+	ui_block_align_calc(block, CTX_wm_region(C));
 	if ((block->flag & UI_BLOCK_LOOP) && (block->flag & UI_BLOCK_NUMSELECT)) {
 		ui_menu_block_set_keyaccels(block); /* could use a different flag to check */
 	}
@@ -1420,7 +1420,6 @@ int ui_but_is_pushed_ex(uiBut *but, double *value)
 				break;
 			case UI_BTYPE_ROW:
 			case UI_BTYPE_LISTROW:
-			case UI_BTYPE_TAB:
 				UI_GET_BUT_VALUE_INIT(but, *value);
 				/* support for rna enum buts */
 				if (but->rnaprop && (RNA_property_flag(but->rnaprop) & PROP_ENUM_FLAG)) {
@@ -1430,6 +1429,18 @@ int ui_but_is_pushed_ex(uiBut *but, double *value)
 					if (*value == (double)but->hardmax) is_push = true;
 				}
 				break;
+			case UI_BTYPE_TAB:
+				if (but->rnaprop && but->custom_data) {
+					/* uiBut.custom_data points to data this tab represents (e.g. workspace).
+					 * uiBut.rnapoin/prop store an active value (e.g. active workspace). */
+					if (RNA_property_type(but->rnaprop) == PROP_POINTER) {
+						PointerRNA active_ptr = RNA_property_pointer_get(&but->rnapoin, but->rnaprop);
+						if (active_ptr.data == but->custom_data) {
+							is_push = true;
+						}
+					}
+				}
+				break;
 			default:
 				is_push = -1;
 				break;
@@ -1915,7 +1926,7 @@ static bool ui_but_icon_extra_is_visible_text_clear(const uiBut *but)
 
 static bool ui_but_icon_extra_is_visible_search_unlink(const uiBut *but)
 {
-	BLI_assert(but->type == UI_BTYPE_SEARCH_MENU);
+	BLI_assert(ELEM(but->type, UI_BTYPE_SEARCH_MENU, UI_BTYPE_TAB));
 	return ((but->editstr == NULL) &&
 	        (but->drawstr[0] != '\0') &&
 	        (but->flag & UI_BUT_VALUE_CLEAR));
@@ -1958,6 +1969,11 @@ uiButExtraIconType ui_but_icon_extra_get(uiBut *but)
 				return UI_BUT_ICONEXTRA_EYEDROPPER;
 			}
 			break;
+		case UI_BTYPE_TAB:
+			if (ui_but_icon_extra_is_visible_search_unlink(but)) {
+				return UI_BUT_ICONEXTRA_CLEAR;
+			}
+			break;
 		default:
 			break;
 	}
@@ -2071,14 +2087,23 @@ void ui_but_string_get_ex(uiBut *but, char *str, const size_t maxlen, const int
 		*r_use_exp_float = false;
 	}
 
-	if (but->rnaprop && ELEM(but->type, UI_BTYPE_TEXT, UI_BTYPE_SEARCH_MENU)) {
+	if (but->rnaprop && ELEM(but->type, UI_BTYPE_TEXT, UI_BTYPE_SEARCH_MENU, UI_BTYPE_TAB)) {
 		PropertyType type;
 		const char *buf = NULL;
 		int buf_len;
 
 		type = RNA_property_type(but->rnaprop);
 
-		if (type == PROP_STRING) {
+		if ((but->type == UI_BTYPE_TAB) && (but->custom_data)) {
+			StructRNA *ptr_type = RNA_property_pointer_type(&but->rnapoin, but->rnaprop);
+			PointerRNA ptr;
+
+			/* uiBut.custom_data points to data this tab represents (e.g. workspace).
+			 * uiBut.rnapoin/prop store an active value (e.g. active workspace). */
+			RNA_pointer_create(but->rnapoin.id.data, ptr_type, but->custom_data, &ptr);
+			buf = RNA_struct_name_get_alloc(&ptr, str, maxlen, &buf_len);
+		}
+		else if (type == PROP_STRING) {
 			/* RNA string */
 			buf = RNA_property_string_get_alloc(&but->rnapoin, but->rnaprop, str, maxlen, &buf_len);
 		}
@@ -2114,12 +2139,7 @@ void ui_but_string_get_ex(uiBut *but, char *str, const size_t maxlen, const int
 			MEM_freeN((void *)buf);
 		}
 	}
-	else if (but->type == UI_BTYPE_TEXT) {
-		/* string */
-		BLI_strncpy(str, but->poin, maxlen);
-		return;
-	}
-	else if (but->type == UI_BTYPE_SEARCH_MENU) {
+	else if (ELEM(but->type, UI_BTYPE_TEXT, UI_BTYPE_SEARCH_MENU)) {
 		/* string */
 		BLI_strncpy(str, but->poin, maxlen);
 		return;
@@ -2329,18 +2349,16 @@ bool ui_but_string_set(bContext *C, uiBut *but, const char *str)
 				return true;
 			}
 			else if (type == PROP_POINTER) {
-				/* RNA pointer */
-				PointerRNA ptr, rptr;
-				PropertyRNA *prop;
-
 				if (str[0] == '\0') {
 					RNA_property_pointer_set(&but->rnapoin, but->rnaprop, PointerRNA_NULL);
 					return true;
 				}
 				else {
-					ptr = but->rnasearchpoin;
-					prop = but->rnasearchprop;
-					
+					/* RNA pointer */
+					PointerRNA rptr;
+					PointerRNA ptr = but->rnasearchpoin;
+					PropertyRNA *prop = but->rnasearchprop;
+
 					if (prop && RNA_property_collection_lookup_string(&ptr, prop, str, &rptr))
 						RNA_property_pointer_set(&but->rnapoin, but->rnaprop, rptr);
 
@@ -2362,6 +2380,21 @@ bool ui_but_string_set(bContext *C, uiBut *but, const char *str)
 			}
 		}
 	}
+	else if (but->type == UI_BTYPE_TAB) {
+		if (but->rnaprop && but->custom_data) {
+			StructRNA *ptr_type = RNA_property_pointer_type(&but->rnapoin, but->rnaprop);
+			PointerRNA ptr;
+			PropertyRNA *prop;
+
+			/* uiBut.custom_data points to data this tab represents (e.g. workspace).
+			 * uiBut.rnapoin/prop store an active value (e.g. active workspace). */
+			RNA_pointer_create(but->rnapoin.id.data, ptr_type, but->custom_data, &ptr);
+			prop = RNA_struct_name_property(ptr_type);
+			if (RNA_property_editable(&ptr, prop)) {
+				RNA_property_string_set(&ptr, prop, str);
+			}
+		}
+	}
 	else if (but->type == UI_BTYPE_TEXT) {
 		/* string */
 		if (!but->poin || (str[0] == '\0')) {
@@ -2907,6 +2940,7 @@ void ui_but_update_ex(uiBut *but, const bool validate)
 
 		case UI_BTYPE_TEXT:
 		case UI_BTYPE_SEARCH_MENU:
+		case UI_BTYPE_TAB:
 			if (!but->editstr) {
 				char str[UI_MAX_DRAW_STR];
 
@@ -3030,6 +3064,16 @@ void ui_block_cm_to_display_space_range(uiBlock *block, float *min, float *max)
 	*max = max_fff(UNPACK3(pixel));
 }
 
+static uiBut *ui_but_alloc(const eButType type)
+{
+	switch (type) {
+		case UI_BTYPE_TAB:
+			return MEM_callocN(sizeof(uiButTab), "uiButTab");
+		default:
+			return MEM_callocN(sizeof(uiBut), "uiBut");
+	}
+}
+
 /**
  * \brief ui_def_but is the function that draws many button types
  *
@@ -3063,7 +3107,7 @@ static uiBut *ui_def_but(
 		}
 	}
 
-	but = MEM_callocN(sizeof(uiBut), "uiBut");
+	but = ui_but_alloc(type & BUTTYPE);
 
 	but->type = type & BUTTYPE;
 	but->pointype = type & UI_BUT_POIN_TYPES;
diff --git a/source/blender/editors/interface/interface_align.c b/source/blender/editors/interface/interface_align.c
index 9aeb685a907..1fc38a27303 100644
--- a/source/blender/editors/interface/interface_align.c
+++ b/source/blender/editors/interface/interface_align.c
@@ -320,13 +320,43 @@ static int ui_block_align_butal_cmp(const void *a, const void *b)
 	return 0;
 }
 
+static void ui_block_align_but_to_region(uiBut *but, const ARegion *region)
+{
+	rctf *rect = &but->rect;
+	const float but_width = BLI_rctf_size_x(rect);
+	const float but_height = BLI_rctf_size_y(rect);
+	const float px = U.pixelsize;
+
+	switch (but->drawflag & UI_BUT_ALIGN) {
+		case UI_BUT_ALIGN_TOP:
+			rect->ymax = region->winy + px;
+			rect->ymin = but->rect.ymax - but_height;
+			break;
+		case UI_BUT_ALIGN_DOWN:
+			rect->ymin = -px;
+			rect->ymax = rect->ymin + but_height;
+			break;
+		case UI_BUT_ALIGN_LEFT:
+			rect->xmin = -px;
+			rect->xmax = rect->xmin + but_width;
+			break;
+		case UI_BUT_ALIGN_RIGHT:
+			rect->xmax = region->winx + px;
+			rect->xmin = rect->xmax - but_width;
+			break;
+		default:
+			BLI_assert(0);
+			break;
+	}
+}
+
 /**
  * Compute the alignment of all 'align groups' of buttons in given block.
  *
  * This is using an order-independent algorithm, i.e. alignment of buttons should be OK regardless of order in which
  * they are added to the block.
  */
-void ui_block_align_calc(uiBlock *block)
+void ui_block_align_calc(uiBlock *block, const ARegion *region)
 {
 	uiBut *but;
 	int num_buttons = 0;
@@ -338,10 +368,17 @@ void ui_block_align_calc(uiBlock *block)
 	int side;
 	int i, j;
 
-	/* First loop: we count number of buttons belonging to an align group, and clear their align flag. */
+	/* First loop: we count number of buttons belonging to an align group, and clear their align flag.
+	 * Tabs get some special treatment here, they get aligned to region border. */
 	for (but = block->buttons.first; but; but = but->next) {
-		/* Clear old align flags. */
-		but->drawflag &= ~UI_BUT_ALIGN_ALL;
+		/* special case: tabs need to be aligned to a region border, drawflag tells which one */
+		if (but->type == UI_BTYPE_TAB) {
+			ui_block_align_but_to_region(but, region);
+		}
+		else {
+			/* Clear old align flags. */
+			but->drawflag &= ~UI_BUT_ALIGN_ALL;
+		}
 
 		if (but->alignnr != 0) {
 			num_buttons++;
diff --git a/source/blender/editors/interface/interface_handlers.c b/source/blender/editors/interface/interface_handlers.c
index 63fe440b36c..9e88c3cbb7f 100644
--- a/source/blender/editors/interface/interface_handlers.c
+++ b/source/blender/editors/interface/interface_handlers.c
@@ -931,6 +931,20 @@ static void ui_apply_but_TEX(bContext *C, uiBut *but, uiHandleButtonData *data)
 	data->applied = true;
 }
 
+static void ui_apply_but_TAB(bContext *C, uiBut *but, uiHandleButtonData *data)
+{
+	if (data->str) {
+		ui_but_string_set(C, but, data->str);
+		ui_but_update_edited(but);
+	}
+	else {
+		ui_apply_but_func(C, but);
+	}
+
+	data->retval = but->retval;
+	data->applied = true;
+}
+
 static void ui_apply_but_NUM(bContext *C, uiBut *but, uiHandleButtonData *data)
 {
 	if (data->str) {
@@ -1892,9 +1906,11 @@ static void ui_apply_but(bContext *C, uiBlock *block, uiBut *but, uiHandleButton
 			break;
 		case UI_BTYPE_ROW:
 		case UI_BTYPE_LISTROW:
-		case UI_BTYPE_TAB:
 			ui_apply_but_ROW(C, block, but, data);
 			break;
+		case UI_BTYPE_TAB:
+			ui_apply_but_TAB(C, but, data);
+			break;
 		case UI_BTYPE_SCROLL:
 		case UI_BTYPE_GRIP:
 		case UI_BTYPE_NUM:
@@ -3649,18 +3665,6 @@ static int ui_do_but_KEYEVT(
 	return WM_UI_HANDLER_CONTINUE;
 }
 
-static int ui_do_but_TAB(bContext *C, uiBut *but, uiHandleButtonData *data, const wmEvent *event)
-{
-	if (data->state == BUTTON_STATE_HIGHLIGHT) {
-		if (ELEM(event->type, LEFTMOUSE, PADENTER, RETKEY) && event->val == KM_PRESS) {
-			button_activate_state(C, but, BUTTON_STATE_EXIT);
-			return WM_UI_HANDLER_CONTINUE;
-		}
-	}
-
-	return WM_UI_HANDLER_CONTINUE;
-}
-
 static bool ui_but_is_mouse_over_icon_extra(const ARegion *region, uiBut *but, const int mouse_xy[2])
 {
 	int x = mouse_xy[0], y = mouse_xy[1];
@@ -3676,6 +3680,43 @@ static bool ui_but_is_mouse_over_icon_extra(const ARegion *region, uiBut *but, c
 	return BLI_rcti_isect_pt(&icon_rect, x, y);
 }
 
+static int ui_do_but_TAB(bContext *C, uiBlock *block, uiBut *but, uiHandleButtonData *data, const wmEvent *event)
+{
+	if (data->state == BUTTON_STATE_HIGHLIGHT) {
+		if ((event->type == LEFTMOUSE) &&
+		    ((event->val == KM_DBL_CLICK) || event->ctrl))
+		{
+			button_activate_state(C, but, BUTTON_STATE_TEXT_EDITING);
+			return WM_UI_HANDLER_BREAK;
+		}
+		else if (ELEM(event->type, LEFTMOUSE, PADENTER, RETKEY) && (event->val == KM_CLICK)) {
+			const bool has_icon_extra = ui_but_icon_extra_get(but) == UI_BUT_ICONEXTRA_CLEAR;
+
+			if (has_icon_extra && ui_but_is_mouse_over_icon_extra(data->region, but, &event->x)) {
+				uiButTab *tab = (uiButTab *)but;
+				wmOperatorType *ot_backup = but->optype;
+
+				but->optype = tab->unlink_ot;
+				/* Force calling unlink/delete operator. */
+				ui_apply_but(C, block, but, data, true);
+				but->optype = ot_backup;
+			}
+			button_activate_state(C, but, BUTTON_STATE_EXIT);
+			return WM_UI_HANDLER_BREAK;
+		}
+	}
+	else if (data->state == BUTTON_STATE_TEXT_EDITING) {
+		ui_do_but_textedit(C, block, but, data, event);
+		return WM_UI_HANDLER_BREAK;
+	}
+	else if (data->state == BUTTON_STATE_TEXT_SELECTING) {
+		ui_do_but_textedit_select(C, block, but, data, event);
+		return WM_UI_HANDLER_BREAK;
+	}
+
+	return WM_UI_HANDLER_CONTINUE;
+}
+
 static int ui_do_but_TEX(
         bContext *C, uiBlock *block, uiBut *but,
         uiHandleButtonData *data, const wmEvent *event)
@@ -6946,7 +6987,7 @@ static int ui_do_button(bContext *C, uiBlock *block, uiBut *but, const wmEvent *
 			retval = ui_do_but_HOTKEYEVT(C, but, data, event);
 			break;
 		case UI_BTYPE_TAB:
-			retval = ui_do_but_TAB(C, but, data, event);
+			retval = ui_do_but_TAB(C, block, but, data, event);
 			break;
 		case UI_BTYPE_BUT_TOGGLE:
 		case UI_BTYPE_TOGGLE:
@@ -7216,15 +7257,14 @@ bool ui_but_is_active(ARegion *ar)
 /* is called by notifier */
 void UI_screen_free_active_but(const bContext *C, bScreen *screen)
 {
-	ScrArea *sa = screen->areabase.first;
-	
-	for (; sa; sa = sa->next) {
-		ARegion *ar = sa->regionbase.first;
-		for (; ar; ar = ar->next) {
-			uiBut *but = ui_but_find_active_in_region(ar);
+	wmWindow *win = CTX_wm_window(C);
+
+	ED_screen_areas_iter(win, screen, area) {
+		for (ARegion *region = area->regionbase.first; region; region = region->next) {
+			uiBut *but = ui_but_find_active_in_region(region);
 			if (but) {
 				uiHandleButtonData *data = but->active;
-				
+
 				if (data->menu == NULL && data->searchbox == NULL)
 					if (data->state == BUTTON_STATE_HIGHLIGHT)
 						ui_but_active_free(C, but);
diff --git a/source/blender/editors/interface/interface_intern.h b/source/blender/editors/interface/interface_intern.h
index 17ea50d5465..e71f36018e3 100644
--- a/source/blender/editors/interface/interface_intern.h
+++ b/source/blender/editors/interface/interface_intern.h
@@ -330,6 +330,11 @@ struct uiBut {
 	uiBlock *block;
 };
 
+typedef struct uiButTab {
+	uiBut but;
+	struct wmOperatorType *unlink_ot;
+} uiButTab;
+
 typedef struct ColorPicker {
 	struct ColorPicker *next, *prev;
 	float color_data[3]; /* colr data may be HSV or HSL for now */
@@ -773,7 +778,7 @@ void ui_layout_list_set_labels_active(uiLayout *layout);
 
 /* interface_align.c */
 bool ui_but_can_align(const uiBut *but) ATTR_WARN_UNUSED_RESULT;
-void ui_block_align_calc(uiBlock *block);
+void ui_block_align_calc(uiBlock *block, const ARegion *region);
 
 /* interface_anim.c */
 void ui_but_anim_flag(uiBut *but, float cfra);
diff --git a/source/blender/editors/interface/interface_layout.c b/source/blender/editors/interface/interface_layout.c
index 969367f485c..7193ad64359 100644
--- a/source/blender/editors/interface/interface_layout.c
+++ b/source/blender/editors/interface/interface_layout.c
@@ -392,7 +392,7 @@ static void ui_layer_but_cb(bContext *C, void *arg_but, void *arg_index)
 static void ui_item_array(
         uiLayout *layout, uiBlock *block, const char *name, int icon,
         PointerRNA *ptr, PropertyRNA *prop, int len, int x, int y, int w, int UNUSED(h),
-        bool expand, bool slider, bool toggle, bool icon_only)
+        bool expand, bool slider, bool toggle, bool icon_only, bool compact)
 {
 	uiStyle *style = layout->root->style;
 	uiBut *but;
@@ -541,9 +541,18 @@ static void ui_item_array(
 			}
 
 			for (a = 0; a < len; a++) {
-				if (!icon_only) str[0] = RNA_property_array_item_char(prop, a);
-				if (boolarr) icon = boolarr[a] ? ICON_CHECKBOX_HLT : ICON_CHECKBOX_DEHLT;
-				but = uiDefAutoButR(block, ptr, prop, a, str, icon, 0, 0, w, UI_UNIT_Y);
+				int width_item;
+
+				if (!icon_only) {
+					str[0] = RNA_property_array_item_char(prop, a);
+				}
+				if (boolarr) {
+					icon = boolarr[a] ? ICON_CHECKBOX_HLT : ICON_CHECKBOX_DEHLT;
+				}
+				width_item = (compact && type == PROP_BOOLEAN) ?
+				                 min_ii(w, ui_text_icon_width(layout, str, icon, false)) : w;
+
+				but = uiDefAutoButR(block, ptr, prop, a, str, icon, 0, 0, width_item, UI_UNIT_Y);
 				if (slider && but->type == UI_BTYPE_NUM)
 					but->type = UI_BTYPE_NUM_SLIDER;
 				if (toggle && but->type == UI_BTYPE_CHECKBOX)
@@ -669,27 +678,38 @@ static void ui_keymap_but_cb(bContext *UNUSED(C), void *but_v, void *UNUSED(key_
 	RNA_boolean_set(&but->rnapoin, "oskey", (but->modifier_key & KM_OSKEY) != 0);
 }
 
-/* create label + button for RNA property */
-static uiBut *ui_item_with_label(uiLayout *layout, uiBlock *block, const char *name, int icon, PointerRNA *ptr, PropertyRNA *prop, int index, int x, int y, int w, int h, int flag)
+/**
+ * Create label + button for RNA property
+ *
+ * \param w_hint: For varying width layout, this becomes the label width.
+ *                Otherwise it's used to fit both items into it.
+ **/
+static uiBut *ui_item_with_label(
+        uiLayout *layout, uiBlock *block, const char *name, int icon,
+        PointerRNA *ptr, PropertyRNA *prop, int index,
+        int x, int y, int w_hint, int h, int flag)
 {
 	uiLayout *sub;
 	uiBut *but = NULL;
 	PropertyType type;
 	PropertySubType subtype;
-	int labelw;
+	int prop_but_width = w_hint;
 
 	sub = uiLayoutRow(layout, layout->align);
 	UI_block_layout_set_current(block, sub);
 
 	if (name[0]) {
-		/* XXX UI_fontstyle_string_width is not accurate */
-#if 0
-		labelw = UI_fontstyle_string_width(fstyle, name);
-		CLAMP(labelw, w / 4, 3 * w / 4);
-#endif
-		labelw = w / 3;
-		uiDefBut(block, UI_BTYPE_LABEL, 0, name, x, y, labelw, h, NULL, 0.0, 0.0, 0, 0, "");
-		w = w - labelw;
+		int w_label;
+
+		if (ui_layout_vary_direction(layout) == UI_ITEM_VARY_X) {
+			/* w_hint is width for label in this case. Use a default width for property button(s) */
+			prop_but_width = UI_UNIT_X * 5;
+			w_label = w_hint;
+		}
+		else {
+			w_label = w_hint / 3;
+		}
+		uiDefBut(block, UI_BTYPE_LABEL, 0, name, x, y, w_label, h, NULL, 0.0, 0.0, 0, 0, "");
 	}
 
 	type = RNA_property_type(prop);
@@ -697,14 +717,14 @@ static uiBut *ui_item_with_label(uiLayout *layout, uiBlock *block, const char *n
 
 	if (subtype == PROP_FILEPATH || subtype == PROP_DIRPATH) {
 		UI_block_layout_set_current(block, uiLayoutRow(sub, true));
-		but = uiDefAutoButR(block, ptr, prop, index, "", icon, x, y, w - UI_UNIT_X, h);
+		but = uiDefAutoButR(block, ptr, prop, index, "", icon, x, y, prop_but_width - UI_UNIT_X, h);
 
 		/* BUTTONS_OT_file_browse calls UI_context_active_but_prop_get_filebrowser */
 		uiDefIconButO(block, UI_BTYPE_BUT, subtype == PROP_DIRPATH ? "BUTTONS_OT_directory_browse" : "BUTTONS_OT_file_browse",
 		              WM_OP_INVOKE_DEFAULT, ICON_FILESEL, x, y, UI_UNIT_X, h, NULL);
 	}
 	else if (flag & UI_ITEM_R_EVENT) {
-		but = uiDefButR_prop(block, UI_BTYPE_KEY_EVENT, 0, name, x, y, w, h, ptr, prop, index, 0, 0, -1, -1, NULL);
+		but = uiDefButR_prop(block, UI_BTYPE_KEY_EVENT, 0, name, x, y, prop_but_width, h, ptr, prop, index, 0, 0, -1, -1, NULL);
 	}
 	else if (flag & UI_ITEM_R_FULL_EVENT) {
 		if (RNA_struct_is_a(ptr->type, &RNA_KeyMapItem)) {
@@ -712,14 +732,17 @@ static uiBut *ui_item_with_label(uiLayout *layout, uiBlock *block, const char *n
 
 			WM_keymap_item_to_string(ptr->data, false, buf, sizeof(buf));
 
-			but = uiDefButR_prop(block, UI_BTYPE_HOTKEY_EVENT, 0, buf, x, y, w, h, ptr, prop, 0, 0, 0, -1, -1, NULL);
+			but = uiDefButR_prop(block, UI_BTYPE_HOTKEY_EVENT, 0, buf, x, y, prop_but_width, h, ptr, prop, 0, 0, 0, -1, -1, NULL);
 			UI_but_func_set(but, ui_keymap_but_cb, but, NULL);
 			if (flag & UI_ITEM_R_IMMEDIATE)
 				UI_but_flag_enable(but, UI_BUT_IMMEDIATE);
 		}
 	}
-	else
-		but = uiDefAutoButR(block, ptr, prop, index, (type == PROP_ENUM && !(flag & UI_ITEM_R_ICON_ONLY)) ? NULL : "", icon, x, y, w, h);
+	else {
+		const char *str = (type == PROP_ENUM && !(flag & UI_ITEM_R_ICON_ONLY)) ? NULL : "";
+		but = uiDefAutoButR(block, ptr, prop, index, str, icon,
+		                    x, y, prop_but_width, h);
+	}
 
 	UI_block_layout_set_current(block, layout);
 	return but;
@@ -1302,8 +1325,10 @@ void uiItemO(uiLayout *layout, const char *name, int icon, const char *opname)
 /* RNA property items */
 
 static void ui_item_rna_size(
-        uiLayout *layout, const char *name, int icon, PointerRNA *ptr, PropertyRNA *prop,
-        int index, bool icon_only, int *r_w, int *r_h)
+        uiLayout *layout, const char *name, int icon,
+        PointerRNA *ptr, PropertyRNA *prop,
+        int index, bool icon_only, bool compact,
+        int *r_w, int *r_h)
 {
 	PropertyType type;
 	PropertySubType subtype;
@@ -1329,7 +1354,7 @@ static void ui_item_rna_size(
 			RNA_property_enum_items_gettexted(layout->root->block->evil_C, ptr, prop, &item_array, NULL, &free);
 			for (item = item_array; item->identifier; item++) {
 				if (item->identifier[0]) {
-					w = max_ii(w, ui_text_icon_width(layout, item->name, item->icon, 0));
+					w = max_ii(w, ui_text_icon_width(layout, item->name, item->icon, compact));
 				}
 			}
 			if (free) {
@@ -1340,12 +1365,13 @@ static void ui_item_rna_size(
 
 	if (!w) {
 		if (type == PROP_ENUM && icon_only) {
-			w = ui_text_icon_width(layout, "", ICON_BLANK1, 0);
+			w = ui_text_icon_width(layout, "", ICON_BLANK1, compact);
 			if (index != RNA_ENUM_VALUE)
 				w += 0.6f * UI_UNIT_X;
 		}
 		else {
-			w = ui_text_icon_width(layout, name, icon, 0);
+			/* not compact for float/int buttons, looks too squashed */
+			w = ui_text_icon_width(layout, name, icon, ELEM(type, PROP_FLOAT, PROP_INT) ? false : compact);
 		}
 	}
 	h = UI_UNIT_Y;
@@ -1382,7 +1408,7 @@ void uiItemFullR(uiLayout *layout, PointerRNA *ptr, PropertyRNA *prop, int index
 	PropertyType type;
 	char namestr[UI_MAX_NAME_STR];
 	int len, w, h;
-	bool slider, toggle, expand, icon_only, no_bg;
+	bool slider, toggle, expand, icon_only, no_bg, compact;
 	bool is_array;
 
 	UI_block_layout_set_current(block, layout);
@@ -1415,7 +1441,12 @@ void uiItemFullR(uiLayout *layout, PointerRNA *ptr, PropertyRNA *prop, int index
 		name = ui_item_name_add_colon(name, namestr);
 	}
 	else if (type == PROP_ENUM && index != RNA_ENUM_VALUE) {
-		name = ui_item_name_add_colon(name, namestr);
+		if (flag & UI_ITEM_R_COMPACT) {
+			name = "";
+		}
+		else {
+			name = ui_item_name_add_colon(name, namestr);
+		}
 	}
 
 	/* menus and pie-menus don't show checkbox without this */
@@ -1443,16 +1474,19 @@ void uiItemFullR(uiLayout *layout, PointerRNA *ptr, PropertyRNA *prop, int index
 	expand = (flag & UI_ITEM_R_EXPAND) != 0;
 	icon_only = (flag & UI_ITEM_R_ICON_ONLY) != 0;
 	no_bg = (flag & UI_ITEM_R_NO_BG) != 0;
+	compact = (flag & UI_ITEM_R_COMPACT) != 0;
 
 	/* get size */
-	ui_item_rna_size(layout, name, icon, ptr, prop, index, icon_only, &w, &h);
+	ui_item_rna_size(layout, name, icon, ptr, prop, index, icon_only, compact, &w, &h);
 
 	if (no_bg)
 		UI_block_emboss_set(block, UI_EMBOSS_NONE);
 	
 	/* array property */
 	if (index == RNA_NO_INDEX && is_array)
-		ui_item_array(layout, block, name, icon, ptr, prop, len, 0, 0, w, h, expand, slider, toggle, icon_only);
+		ui_item_array(
+		            layout, block, name, icon, ptr, prop, len, 0, 0, w, h,
+		            expand, slider, toggle, icon_only, compact);
 	/* enum item */
 	else if (type == PROP_ENUM && index == RNA_ENUM_VALUE) {
 		if (icon && name[0] && !icon_only)
@@ -1641,6 +1675,7 @@ void uiItemsEnumR(uiLayout *layout, struct PointerRNA *ptr, const char *propname
 
 /* Pointer RNA button with search */
 
+
 static void search_id_collection(StructRNA *ptype, PointerRNA *ptr, PropertyRNA **prop)
 {
 	StructRNA *srna;
@@ -1771,7 +1806,7 @@ void uiItemPointerR(uiLayout *layout, struct PointerRNA *ptr, const char *propna
 	/* create button */
 	block = uiLayoutGetBlock(layout);
 
-	ui_item_rna_size(layout, name, icon, ptr, prop, 0, 0, &w, &h);
+	ui_item_rna_size(layout, name, icon, ptr, prop, 0, 0, false, &w, &h);
 	w += UI_UNIT_X; /* X icon needs more space */
 	but = ui_item_with_label(layout, block, name, icon, ptr, prop, 0, 0, 0, w, h, 0);
 
diff --git a/source/blender/editors/interface/interface_templates.c b/source/blender/editors/interface/interface_templates.c
index ae2b8c8060c..4af63f2bbcb 100644
--- a/source/blender/editors/interface/interface_templates.c
+++ b/source/blender/editors/interface/interface_templates.c
@@ -120,7 +120,9 @@ static void template_add_button_search_menu(
 
 	if (use_previews) {
 		ARegion *region = CTX_wm_region(C);
-		const bool use_big_size = (region->regiontype != RGN_TYPE_HEADER); /* silly check, could be more generic */
+		ScrArea *area = CTX_wm_area(C);
+		/* XXX ugly top-bar exception */
+		const bool use_big_size = (region->regiontype != RGN_TYPE_HEADER) && (area->spacetype != SPACE_TOPBAR); /* silly check, could be more generic */
 		/* Ugly exception for screens here, drawing their preview in icon size looks ugly/useless */
 		const bool use_preview_icon = use_big_size || (id && (GS(id->name) != ID_SCR));
 		const short width = UI_UNIT_X * (use_big_size ? 6 : 1.6f);
@@ -238,7 +240,7 @@ typedef struct TemplateID {
 } TemplateID;
 
 /* Search browse menu, assign  */
-static void id_search_call_cb(bContext *C, void *arg_template, void *item)
+static void template_ID_set_property_cb(bContext *C, void *arg_template, void *item)
 {
 	TemplateID *template_ui = (TemplateID *)arg_template;
 
@@ -379,7 +381,7 @@ static uiBlock *id_search_menu(bContext *C, ARegion *ar, void *arg_litem)
 	}
 
 	return template_common_search_menu(
-	               C, ar, id_search_cb_p, &template_ui, id_search_call_cb, active_item_ptr.data,
+	               C, ar, id_search_cb_p, &template_ui, template_ID_set_property_cb, active_item_ptr.data,
 	               template_ui.prv_rows, template_ui.prv_cols);
 }
 
@@ -570,6 +572,67 @@ static const char *template_id_context(StructRNA *type)
 }
 #endif
 
+static uiBut *template_id_def_new_but(
+        uiBlock *block, const ID *id, const TemplateID *template_ui, StructRNA *type,
+        const char * const newop, const bool editable, const bool id_open, const bool use_tab_but)
+{
+	ID *idfrom = template_ui->ptr.id.data;
+	uiBut *but;
+	const int w = id ? UI_UNIT_X : id_open ? UI_UNIT_X * 3 : UI_UNIT_X * 6;
+	const int but_type = use_tab_but ? UI_BTYPE_TAB : UI_BTYPE_BUT;
+
+	/* i18n markup, does nothing! */
+	BLT_I18N_MSGID_MULTI_CTXT("New", BLT_I18NCONTEXT_DEFAULT,
+	                                 BLT_I18NCONTEXT_ID_SCENE,
+	                                 BLT_I18NCONTEXT_ID_OBJECT,
+	                                 BLT_I18NCONTEXT_ID_MESH,
+	                                 BLT_I18NCONTEXT_ID_CURVE,
+	                                 BLT_I18NCONTEXT_ID_METABALL,
+	                                 BLT_I18NCONTEXT_ID_MATERIAL,
+	                                 BLT_I18NCONTEXT_ID_TEXTURE,
+	                                 BLT_I18NCONTEXT_ID_IMAGE,
+	                                 BLT_I18NCONTEXT_ID_LATTICE,
+	                                 BLT_I18NCONTEXT_ID_LAMP,
+	                                 BLT_I18NCONTEXT_ID_CAMERA,
+	                                 BLT_I18NCONTEXT_ID_WORLD,
+	                                 BLT_I18NCONTEXT_ID_SCREEN,
+	                                 BLT_I18NCONTEXT_ID_TEXT,
+	);
+	BLT_I18N_MSGID_MULTI_CTXT("New", BLT_I18NCONTEXT_ID_SPEAKER,
+	                                 BLT_I18NCONTEXT_ID_SOUND,
+	                                 BLT_I18NCONTEXT_ID_ARMATURE,
+	                                 BLT_I18NCONTEXT_ID_ACTION,
+	                                 BLT_I18NCONTEXT_ID_NODETREE,
+	                                 BLT_I18NCONTEXT_ID_BRUSH,
+	                                 BLT_I18NCONTEXT_ID_PARTICLESETTINGS,
+	                                 BLT_I18NCONTEXT_ID_GPENCIL,
+	                                 BLT_I18NCONTEXT_ID_FREESTYLELINESTYLE,
+	                                 BLT_I18NCONTEXT_ID_WORKSPACE,
+	                                 BLT_I18NCONTEXT_ID_LIGHTPROBE,
+	);
+
+	if (newop) {
+		but = uiDefIconTextButO(block, but_type, newop, WM_OP_INVOKE_DEFAULT, ICON_ZOOMIN,
+		                        (id) ? "" : CTX_IFACE_(template_id_context(type), "New"), 0, 0, w, UI_UNIT_Y, NULL);
+		UI_but_funcN_set(but, template_id_cb, MEM_dupallocN(template_ui), SET_INT_IN_POINTER(UI_ID_ADD_NEW));
+	}
+	else {
+		but = uiDefIconTextBut(block, but_type, 0, ICON_ZOOMIN, (id) ? "" : CTX_IFACE_(template_id_context(type), "New"),
+		                       0, 0, w, UI_UNIT_Y, NULL, 0, 0, 0, 0, NULL);
+		UI_but_funcN_set(but, template_id_cb, MEM_dupallocN(template_ui), SET_INT_IN_POINTER(UI_ID_ADD_NEW));
+	}
+
+	if ((idfrom && idfrom->lib) || !editable) {
+		UI_but_flag_enable(but, UI_BUT_DISABLED);
+	}
+
+#ifndef WITH_INTERNATIONAL
+	UNUSED_VARS(type);
+#endif
+
+	return but;
+}
+
 static void template_ID(
         bContext *C, uiLayout *layout, TemplateID *template_ui, StructRNA *type, int flag,
         const char *newop, const char *openop, const char *unlinkop)
@@ -672,51 +735,7 @@ static void template_ID(
 	}
 	
 	if (flag & UI_ID_ADD_NEW) {
-		int w = id ? UI_UNIT_X : (flag & UI_ID_OPEN) ? UI_UNIT_X * 3 : UI_UNIT_X * 6;
-		
-		/* i18n markup, does nothing! */
-		BLT_I18N_MSGID_MULTI_CTXT("New", BLT_I18NCONTEXT_DEFAULT,
-		                                 BLT_I18NCONTEXT_ID_SCENE,
-		                                 BLT_I18NCONTEXT_ID_OBJECT,
-		                                 BLT_I18NCONTEXT_ID_MESH,
-		                                 BLT_I18NCONTEXT_ID_CURVE,
-		                                 BLT_I18NCONTEXT_ID_METABALL,
-		                                 BLT_I18NCONTEXT_ID_MATERIAL,
-		                                 BLT_I18NCONTEXT_ID_TEXTURE,
-		                                 BLT_I18NCONTEXT_ID_IMAGE,
-		                                 BLT_I18NCONTEXT_ID_LATTICE,
-		                                 BLT_I18NCONTEXT_ID_LAMP,
-		                                 BLT_I18NCONTEXT_ID_CAMERA,
-		                                 BLT_I18NCONTEXT_ID_WORLD,
-		                                 BLT_I18NCONTEXT_ID_SCREEN,
-		                                 BLT_I18NCONTEXT_ID_TEXT,
-		);
-		BLT_I18N_MSGID_MULTI_CTXT("New", BLT_I18NCONTEXT_ID_SPEAKER,
-		                                 BLT_I18NCONTEXT_ID_SOUND,
-		                                 BLT_I18NCONTEXT_ID_ARMATURE,
-		                                 BLT_I18NCONTEXT_ID_ACTION,
-		                                 BLT_I18NCONTEXT_ID_NODETREE,
-		                                 BLT_I18NCONTEXT_ID_BRUSH,
-		                                 BLT_I18NCONTEXT_ID_PARTICLESETTINGS,
-		                                 BLT_I18NCONTEXT_ID_GPENCIL,
-		                                 BLT_I18NCONTEXT_ID_FREESTYLELINESTYLE,
-		                                 BLT_I18NCONTEXT_ID_WORKSPACE,
-		                                 BLT_I18NCONTEXT_ID_LIGHTPROBE,
-		);
-		
-		if (newop) {
-			but = uiDefIconTextButO(block, UI_BTYPE_BUT, newop, WM_OP_INVOKE_DEFAULT, ICON_ZOOMIN,
-			                        (id) ? "" : CTX_IFACE_(template_id_context(type), "New"), 0, 0, w, UI_UNIT_Y, NULL);
-			UI_but_funcN_set(but, template_id_cb, MEM_dupallocN(template_ui), SET_INT_IN_POINTER(UI_ID_ADD_NEW));
-		}
-		else {
-			but = uiDefIconTextBut(block, UI_BTYPE_BUT, 0, ICON_ZOOMIN, (id) ? "" : CTX_IFACE_(template_id_context(type), "New"),
-			                       0, 0, w, UI_UNIT_Y, NULL, 0, 0, 0, 0, NULL);
-			UI_but_funcN_set(but, template_id_cb, MEM_dupallocN(template_ui), SET_INT_IN_POINTER(UI_ID_ADD_NEW));
-		}
-
-		if ((idfrom && idfrom->lib) || !editable)
-			UI_but_flag_enable(but, UI_BUT_DISABLED);
+		template_id_def_new_but(block, id, template_ui, type, newop, editable, flag & UI_ID_OPEN, false);
 	}
 
 	/* Due to space limit in UI - skip the "open" icon for packed data, and allow to unpack.
@@ -785,9 +804,57 @@ static void template_ID(
 	UI_block_align_end(block);
 }
 
+static void template_ID_tabs(
+        bContext *C, uiLayout *layout, TemplateID *template, StructRNA *type, int flag,
+        const char *newop, const char *UNUSED(openop), const char *unlinkop)
+{
+	const ARegion *region = CTX_wm_region(C);
+	const PointerRNA active_ptr = RNA_property_pointer_get(&template->ptr, template->prop);
+	const int but_align = (region->alignment == RGN_ALIGN_TOP) ? UI_BUT_ALIGN_DOWN : UI_BUT_ALIGN_TOP;
+
+	uiBlock *block = uiLayoutGetBlock(layout);
+	uiStyle *style = UI_style_get_dpi();
+
+
+	for (ID *id = template->idlb->first; id; id = id->next) {
+		wmOperatorType *unlink_ot = WM_operatortype_find(unlinkop, false);
+		const bool is_active = active_ptr.data == id;
+		const unsigned int but_width = UI_fontstyle_string_width(&style->widgetlabel, id->name + 2) + UI_UNIT_X +
+		                               (is_active ? ICON_DEFAULT_WIDTH_SCALE : 0);
+		uiButTab *tab;
+
+		tab = (uiButTab *)uiDefButR_prop(
+		        block, UI_BTYPE_TAB, 0, "", 0, 0, but_width, UI_UNIT_Y,
+		        &template->ptr, template->prop, 0, 0.0f,
+		        sizeof(id->name) - 2, 0.0f, 0.0f, "");
+		UI_but_funcN_set(&tab->but, template_ID_set_property_cb, MEM_dupallocN(template), id);
+		tab->but.custom_data = (void *)id;
+		tab->unlink_ot = unlink_ot;
+
+		if (is_active) {
+			UI_but_flag_enable(&tab->but, UI_BUT_VALUE_CLEAR);
+		}
+		UI_but_drawflag_enable(&tab->but, but_align);
+	}
+
+	if (flag & UI_ID_ADD_NEW) {
+		const bool editable = RNA_property_editable(&template->ptr, template->prop);
+		uiBut *but;
+
+		if (active_ptr.type) {
+			type = active_ptr.type;
+		}
+
+		but = template_id_def_new_but(block, active_ptr.data, template, type, newop, editable, flag & UI_ID_OPEN, true);
+		UI_but_drawflag_enable(but, but_align);
+	}
+}
+
 static void ui_template_id(
-        uiLayout *layout, bContext *C, PointerRNA *ptr, const char *propname, const char *newop,
-        const char *openop, const char *unlinkop, int flag, int prv_rows, int prv_cols, int filter)
+        uiLayout *layout, bContext *C,
+        PointerRNA *ptr, const char *propname,
+        const char *newop, const char *openop, const char *unlinkop,
+        int flag, int prv_rows, int prv_cols, int filter, bool use_tabs)
 {
 	TemplateID *template_ui;
 	PropertyRNA *prop;
@@ -828,8 +895,14 @@ static void ui_template_id(
 	 *	- template_ID makes a copy of the template data and assigns it to the relevant buttons
 	 */
 	if (template_ui->idlb) {
-		uiLayoutRow(layout, true);
-		template_ID(C, layout, template_ui, type, flag, newop, openop, unlinkop);
+		if (use_tabs) {
+			uiLayoutRow(layout, false);
+			template_ID_tabs(C, layout, template_ui, type, flag, newop, openop, unlinkop);
+		}
+		else {
+			uiLayoutRow(layout, true);
+			template_ID(C, layout, template_ui, type, flag, newop, openop, unlinkop);
+		}
 	}
 
 	MEM_freeN(template_ui);
@@ -839,23 +912,49 @@ void uiTemplateID(
         uiLayout *layout, bContext *C, PointerRNA *ptr, const char *propname, const char *newop,
         const char *openop, const char *unlinkop, int filter)
 {
-	ui_template_id(layout, C, ptr, propname, newop, openop, unlinkop,
-	               UI_ID_BROWSE | UI_ID_RENAME | UI_ID_DELETE, 0, 0, filter);
+	ui_template_id(
+	        layout, C, ptr, propname,
+	        newop, openop, unlinkop,
+	        UI_ID_BROWSE | UI_ID_RENAME | UI_ID_DELETE,
+	        0, 0, filter, false);
 }
 
 void uiTemplateIDBrowse(
         uiLayout *layout, bContext *C, PointerRNA *ptr, const char *propname, const char *newop,
         const char *openop, const char *unlinkop, int filter)
 {
-	ui_template_id(layout, C, ptr, propname, newop, openop, unlinkop, UI_ID_BROWSE | UI_ID_RENAME, 0, 0, filter);
+	ui_template_id(
+	        layout, C, ptr, propname,
+	        newop, openop, unlinkop,
+	        UI_ID_BROWSE | UI_ID_RENAME,
+	        0, 0, filter, false);
 }
 
 void uiTemplateIDPreview(
         uiLayout *layout, bContext *C, PointerRNA *ptr, const char *propname, const char *newop,
         const char *openop, const char *unlinkop, int rows, int cols, int filter)
 {
-	ui_template_id(layout, C, ptr, propname, newop, openop, unlinkop,
-	               UI_ID_BROWSE | UI_ID_RENAME | UI_ID_DELETE | UI_ID_PREVIEWS, rows, cols, filter);
+	ui_template_id(
+	        layout, C, ptr, propname,
+	        newop, openop, unlinkop,
+	        UI_ID_BROWSE | UI_ID_RENAME | UI_ID_DELETE | UI_ID_PREVIEWS,
+	        rows, cols, filter, false);
+}
+
+/**
+ * Version of #uiTemplateID using tabs.
+ */
+void uiTemplateIDTabs(
+        uiLayout *layout, bContext *C,
+        PointerRNA *ptr, const char *propname,
+        const char *newop, const char *openop, const char *unlinkop,
+        int filter)
+{
+	ui_template_id(
+	        layout, C, ptr, propname,
+	        newop, openop, unlinkop,
+	        UI_ID_BROWSE | UI_ID_RENAME | UI_ID_DELETE,
+	        0, 0, filter, true);
 }
 
 /************************ ID Chooser Template ***************************/
@@ -1429,6 +1528,63 @@ uiLayout *uiTemplateModifier(uiLayout *layout, bContext *C, PointerRNA *ptr)
 	return NULL;
 }
 
+
+/************************ Redo Buttons Template *************************/
+
+#ifdef WITH_REDO_REGION_REMOVAL
+static bool template_operator_redo_property_buts_poll(PointerRNA *UNUSED(ptr), PropertyRNA *prop)
+{
+	return (RNA_property_tags(prop) & OP_PROP_TAG_ADVANCED) == 0;
+}
+
+static void template_operator_redo_property_buts_draw(
+        const bContext *C, wmOperator *op,
+        uiLayout *layout, int layout_flags,
+        bool *r_has_advanced)
+{
+	if (op->type->flag & OPTYPE_MACRO) {
+		for (wmOperator *macro_op = op->macro.first; macro_op; macro_op = macro_op->next) {
+			template_operator_redo_property_buts_draw(C, macro_op, layout, layout_flags, r_has_advanced);
+		}
+	}
+	else {
+		/* Might want to make label_align adjustable somehow. */
+		eAutoPropButsReturn return_info = uiTemplateOperatorPropertyButs(
+		                                          C, layout, op, template_operator_redo_property_buts_poll,
+		                                          UI_BUT_LABEL_ALIGN_NONE, layout_flags);
+		if (return_info & UI_PROP_BUTS_ANY_FAILED_CHECK) {
+			*r_has_advanced = true;
+		}
+	}
+}
+
+void uiTemplateOperatorRedoProperties(uiLayout *layout, bContext *C)
+{
+	wmOperator *op = WM_operator_last_redo(C);
+	uiBlock *block = uiLayoutGetBlock(layout);
+
+	if (op == NULL) {
+		return;
+	}
+
+	/* Repeat button with operator name as text. */
+	uiItemFullO(layout, "SCREEN_OT_repeat_last", RNA_struct_ui_name(op->type->srna),
+	            ICON_NONE, NULL, WM_OP_INVOKE_DEFAULT, 0, NULL);
+
+	if (WM_operator_repeat_check(C, op)) {
+		bool has_advanced = false;
+
+		UI_block_func_set(block, ED_undo_operator_repeat_cb, op, NULL);
+		template_operator_redo_property_buts_draw(C, op, layout, UI_TEMPLATE_OP_PROPS_COMPACT, &has_advanced);
+		UI_block_func_set(block, NULL, NULL, NULL); /* may want to reset to old state instead of NULLing all */
+
+		if (has_advanced) {
+			uiItemO(layout, IFACE_("More..."), ICON_NONE, "SCREEN_OT_redo_last");
+		}
+	}
+}
+#endif
+
 /************************ Constraint Template *************************/
 
 #include "DNA_constraint_types.h"
@@ -3716,11 +3872,14 @@ static void ui_layout_operator_buts__reset_cb(bContext *UNUSED(C), void *op_pt,
  * Draw Operator property buttons for redoing execution with different settings.
  * This function does not initialize the layout, functions can be called on the layout before and after.
  */
-void uiTemplateOperatorPropertyButs(
+eAutoPropButsReturn uiTemplateOperatorPropertyButs(
         const bContext *C, uiLayout *layout, wmOperator *op,
         bool (*check_prop)(struct PointerRNA *, struct PropertyRNA *),
-        const char label_align, const short flag)
+        const eButLabelAlign label_align, const short flag)
 {
+	uiBlock *block = uiLayoutGetBlock(layout);
+	eAutoPropButsReturn return_info = 0;
+
 	if (!op->properties) {
 		IDPropertyTemplate val = {0};
 		op->properties = IDP_New(IDP_GROUP, &val, "wmOperatorProperties");
@@ -3733,14 +3892,14 @@ void uiTemplateOperatorPropertyButs(
 	/* poll() on this operator may still fail, at the moment there is no nice feedback when this happens
 	 * just fails silently */
 	if (!WM_operator_repeat_check(C, op)) {
-		UI_block_lock_set(uiLayoutGetBlock(layout), true, "Operator can't' redo");
+		UI_block_lock_set(block, true, "Operator can't' redo");
 
 		/* XXX, could give some nicer feedback or not show redo panel at all? */
 		uiItemL(layout, IFACE_("* Redo Unsupported *"), ICON_NONE);
 	}
 	else {
 		/* useful for macros where only one of the steps can't be re-done */
-		UI_block_lock_clear(uiLayoutGetBlock(layout));
+		UI_block_lock_clear(block);
 	}
 
 	/* menu */
@@ -3749,7 +3908,7 @@ void uiTemplateOperatorPropertyButs(
 		PointerRNA op_ptr;
 		uiLayout *row;
 
-		uiLayoutGetBlock(layout)->ui_operator = op;
+		block->ui_operator = op;
 
 		row = uiLayoutRow(layout, true);
 		uiItemM(row, (bContext *)C, "WM_MT_operator_presets", NULL, ICON_NONE);
@@ -3768,19 +3927,19 @@ void uiTemplateOperatorPropertyButs(
 		op->type->ui((bContext *)C, op);
 		op->layout = NULL;
 
-		/* UI_LAYOUT_OP_SHOW_EMPTY ignored */
+		/* UI_LAYOUT_OP_SHOW_EMPTY ignored. return_info is ignored too. We could
+		 * allow ot.ui callback to return this, but not needed right now. */
 	}
 	else {
 		wmWindowManager *wm = CTX_wm_manager(C);
 		PointerRNA ptr;
-		int empty;
 
 		RNA_pointer_create(&wm->id, op->type->srna, op->properties, &ptr);
 
 		/* main draw call */
-		empty = uiDefAutoButsRNA(layout, &ptr, check_prop, label_align) == 0;
+		return_info = uiDefAutoButsRNA(layout, &ptr, check_prop, label_align, (flag & UI_TEMPLATE_OP_PROPS_COMPACT));
 
-		if (empty && (flag & UI_TEMPLATE_OP_PROPS_SHOW_EMPTY)) {
+		if ((return_info & UI_PROP_BUTS_NONE_ADDED) && (flag & UI_TEMPLATE_OP_PROPS_SHOW_EMPTY)) {
 			uiItemL(layout, IFACE_("No Properties"), ICON_NONE);
 		}
 	}
@@ -3790,7 +3949,6 @@ void uiTemplateOperatorPropertyButs(
 	 * but this is not so important if this button is drawn in those cases
 	 * (which isn't all that likely anyway) - campbell */
 	if (op->properties->len) {
-		uiBlock *block;
 		uiBut *but;
 		uiLayout *col; /* needed to avoid alignment errors with previous buttons */
 
@@ -3804,7 +3962,6 @@ void uiTemplateOperatorPropertyButs(
 
 	/* set various special settings for buttons */
 	{
-		uiBlock *block = uiLayoutGetBlock(layout);
 		const bool is_popup = (block->flag & UI_BLOCK_KEEP_OPEN) != 0;
 		uiBut *but;
 
@@ -3824,6 +3981,8 @@ void uiTemplateOperatorPropertyButs(
 			}
 		}
 	}
+
+	return return_info;
 }
 
 /************************* Running Jobs Template **************************/
diff --git a/source/blender/editors/interface/interface_utils.c b/source/blender/editors/interface/interface_utils.c
index f0317087ddc..f28da5a666b 100644
--- a/source/blender/editors/interface/interface_utils.c
+++ b/source/blender/editors/interface/interface_utils.c
@@ -157,62 +157,72 @@ uiBut *uiDefAutoButR(uiBlock *block, PointerRNA *ptr, PropertyRNA *prop, int ind
  * \a check_prop callback filters functions to avoid drawing certain properties,
  * in cases where PROP_HIDDEN flag can't be used for a property.
  */
-int uiDefAutoButsRNA(
+eAutoPropButsReturn uiDefAutoButsRNA(
         uiLayout *layout, PointerRNA *ptr,
         bool (*check_prop)(PointerRNA *, PropertyRNA *),
-        const char label_align)
+        const eButLabelAlign label_align, const bool compact)
 {
+	eAutoPropButsReturn return_info = UI_PROP_BUTS_NONE_ADDED;
 	uiLayout *split, *col;
 	int flag;
 	const char *name;
-	int tot = 0;
-
-	assert(ELEM(label_align, '\0', 'H', 'V'));
 
 	RNA_STRUCT_BEGIN (ptr, prop)
 	{
 		flag = RNA_property_flag(prop);
-		if (flag & PROP_HIDDEN || (check_prop && check_prop(ptr, prop) == 0))
+
+		if (flag & PROP_HIDDEN) {
+			continue;
+		}
+		if (check_prop && check_prop(ptr, prop) == 0) {
+			return_info |= UI_PROP_BUTS_ANY_FAILED_CHECK;
 			continue;
+		}
 
-		if (label_align != '\0') {
-			PropertyType type = RNA_property_type(prop);
-			const bool is_boolean = (type == PROP_BOOLEAN && !RNA_property_array_check(prop));
+		switch (label_align) {
+			case UI_BUT_LABEL_ALIGN_COLUMN:
+			case UI_BUT_LABEL_ALIGN_SPLIT_COLUMN:
+			{
+				PropertyType type = RNA_property_type(prop);
+				const bool is_boolean = (type == PROP_BOOLEAN && !RNA_property_array_check(prop));
 
-			name = RNA_property_ui_name(prop);
+				name = RNA_property_ui_name(prop);
 
-			if (label_align == 'V') {
-				col = uiLayoutColumn(layout, true);
+				if (label_align == UI_BUT_LABEL_ALIGN_COLUMN) {
+					col = uiLayoutColumn(layout, true);
 
-				if (!is_boolean)
-					uiItemL(col, name, ICON_NONE);
-			}
-			else {  /* (label_align == 'H') */
-				BLI_assert(label_align == 'H');
-				split = uiLayoutSplit(layout, 0.5f, false);
+					if (!is_boolean)
+						uiItemL(col, name, ICON_NONE);
+				}
+				else {
+					BLI_assert(label_align == UI_BUT_LABEL_ALIGN_SPLIT_COLUMN);
+					split = uiLayoutSplit(layout, 0.5f, false);
 
-				col = uiLayoutColumn(split, false);
-				uiItemL(col, (is_boolean) ? "" : name, ICON_NONE);
-				col = uiLayoutColumn(split, false);
-			}
+					col = uiLayoutColumn(split, false);
+					uiItemL(col, (is_boolean) ? "" : name, ICON_NONE);
+					col = uiLayoutColumn(split, false);
+				}
 
-			/* may meed to add more cases here.
-			 * don't override enum flag names */
+				/* may meed to add more cases here.
+				 * don't override enum flag names */
 
-			/* name is shown above, empty name for button below */
-			name = (flag & PROP_ENUM_FLAG || is_boolean) ? NULL : "";
-		}
-		else {
-			col = layout;
-			name = NULL; /* no smart label alignment, show default name with button */
+				/* name is shown above, empty name for button below */
+				name = (flag & PROP_ENUM_FLAG || is_boolean) ? NULL : "";
+
+				break;
+			}
+			case UI_BUT_LABEL_ALIGN_NONE:
+				col = layout;
+				name = NULL; /* no smart label alignment, show default name with button */
+				break;
 		}
 
-		uiItemFullR(col, ptr, prop, -1, 0, 0, name, ICON_NONE);
-		tot++;
+		uiItemFullR(col, ptr, prop, -1, 0, compact ? UI_ITEM_R_COMPACT : 0, name, ICON_NONE);
+		return_info &= ~UI_PROP_BUTS_NONE_ADDED;
 	}
 	RNA_STRUCT_END;
 
-	return tot;
+	return return_info;
 }
 
 /* *** RNA collection search menu *** */
diff --git a/source/blender/editors/interface/interface_widgets.c b/source/blender/editors/interface/interface_widgets.c
index 7714d065363..e5e89260ed5 100644
--- a/source/blender/editors/interface/interface_widgets.c
+++ b/source/blender/editors/interface/interface_widgets.c
@@ -2289,7 +2289,7 @@ static struct uiWidgetColors wcol_list_item = {
 };
 
 struct uiWidgetColors wcol_tab = {
-	{255, 255, 255, 255},
+	{60, 60, 60, 255},
 	{83, 83, 83, 255},
 	{114, 114, 114, 255},
 	{90, 90, 90, 255},
@@ -3832,16 +3832,20 @@ static void widget_roundbut_exec(uiWidgetColors *wcol, rcti *rect, int state, in
 	widgetbase_draw(&wtb, wcol);
 }
 
-static void widget_tab(uiBut *but, uiWidgetColors *wcol, rcti *rect, int UNUSED(state), int roundboxalign)
+static void widget_tab(uiWidgetColors *wcol, rcti *rect, int state, int roundboxalign)
 {
 	const uiStyle *style = UI_style_get();
-	const float rad = 0.15f * U.widget_unit;
+	const float rad = 0.25f * U.widget_unit;
 	const int fontid = style->widget.uifont_id;
-	const bool is_active = (but->flag & UI_SELECT);
+	const bool is_active = (state & UI_SELECT);
+
+/* Draw shaded outline - Disabled for now, seems incorrect and also looks nicer without it imho ;) */
+//#define USE_TAB_SHADED_HIGHLIGHT
 
 	uiWidgetBase wtb;
 	unsigned char theme_col_tab_highlight[3];
 
+#ifdef USE_TAB_SHADED_HIGHLIGHT
 	/* create outline highlight colors */
 	if (is_active) {
 		interp_v3_v3v3_uchar(theme_col_tab_highlight, (unsigned char *)wcol->inner_sel,
@@ -3851,6 +3855,7 @@ static void widget_tab(uiBut *but, uiWidgetColors *wcol, rcti *rect, int UNUSED(
 		interp_v3_v3v3_uchar(theme_col_tab_highlight, (unsigned char *)wcol->inner,
 		                     (unsigned char *)wcol->outline, 0.12f);
 	}
+#endif
 
 	widget_init(&wtb);
 
@@ -3858,7 +3863,9 @@ static void widget_tab(uiBut *but, uiWidgetColors *wcol, rcti *rect, int UNUSED(
 	round_box_edges(&wtb, roundboxalign, rect, rad);
 
 	/* draw inner */
+#ifdef USE_TAB_SHADED_HIGHLIGHT
 	wtb.draw_outline = 0;
+#endif
 	widgetbase_draw(&wtb, wcol);
 
 	/* We are drawing on top of widget bases. Flush cache. */
@@ -3866,13 +3873,19 @@ static void widget_tab(uiBut *but, uiWidgetColors *wcol, rcti *rect, int UNUSED(
 	UI_widgetbase_draw_cache_flush();
 	glDisable(GL_BLEND);
 
+#ifdef USE_TAB_SHADED_HIGHLIGHT
 	/* draw outline (3d look) */
 	ui_draw_but_TAB_outline(rect, rad, theme_col_tab_highlight, (unsigned char *)wcol->inner);
+#endif
 
 	/* text shadow */
 	BLF_enable(fontid, BLF_SHADOW);
 	BLF_shadow(fontid, 3, (const float[4]){1.0f, 1.0f, 1.0f, 0.25f});
 	BLF_shadow_offset(fontid, 0, -1);
+
+#ifndef USE_TAB_SHADED_HIGHLIGHT
+	UNUSED_VARS(is_active, theme_col_tab_highlight);
+#endif
 }
 
 static void widget_draw_extra_mask(const bContext *C, uiBut *but, uiWidgetType *wt, rcti *rect)
@@ -3963,8 +3976,8 @@ static uiWidgetType *widget_type(uiWidgetTypeEnum type)
 			break;
 
 		case UI_WTYPE_TAB:
-			wt.custom = widget_tab;
 			wt.wcol_theme = &btheme->tui.wcol_tab;
+			wt.draw = widget_tab;
 			break;
 
 		case UI_WTYPE_TOOLTIP:
diff --git a/source/blender/editors/interface/resources.c b/source/blender/editors/interface/resources.c
index d13b7e8ea74..b40ab09036f 100644
--- a/source/blender/editors/interface/resources.c
+++ b/source/blender/editors/interface/resources.c
@@ -165,6 +165,9 @@ const unsigned char *UI_ThemeGetColorPtr(bTheme *btheme, int spacetype, int colo
 				case SPACE_CLIP:
 					ts = &btheme->tclip;
 					break;
+				case SPACE_TOPBAR:
+					ts = &btheme->ttopbar;
+					break;
 				default:
 					ts = &btheme->tv3d;
 					break;
@@ -1225,6 +1228,14 @@ void ui_theme_init_default(void)
 	rgba_char_args_set(btheme->tclip.strip_select, 0xff, 0x8c, 0x00, 0xff);
 	btheme->tclip.handle_vertex_size = 5;
 	ui_theme_space_init_handles_color(&btheme->tclip);
+
+	/* space topbar */
+	char tmp[4];
+	btheme->ttopbar = btheme->tv3d;
+	/* swap colors */
+	copy_v4_v4_char(tmp, btheme->ttopbar.header);
+	copy_v4_v4_char(btheme->ttopbar.header, btheme->ttopbar.tab_inactive);
+	copy_v4_v4_char(btheme->ttopbar.back, tmp);
 }
 
 void ui_style_init_default(void)
@@ -2914,10 +2925,10 @@ void init_userdef_do_versions(void)
 		U.uiflag |= USER_LOCK_CURSOR_ADJUST;
 	}
 
-	if (!USER_VERSION_ATLEAST(280, 1)) {
+	if (!USER_VERSION_ATLEAST(280, 9)) {
 		/* interface_widgets.c */
 		struct uiWidgetColors wcol_tab = {
-			{255, 255, 255, 255},
+			{60, 60, 60, 255},
 			{83, 83, 83, 255},
 			{114, 114, 114, 255},
 			{90, 90, 90, 255},
@@ -2930,7 +2941,14 @@ void init_userdef_do_versions(void)
 		};
 
 		for (bTheme *btheme = U.themes.first; btheme; btheme = btheme->next) {
+			char tmp[4];
+
 			btheme->tui.wcol_tab = wcol_tab;
+			btheme->ttopbar = btheme->tv3d;
+			/* swap colors */
+			copy_v4_v4_char(tmp, btheme->ttopbar.header);
+			copy_v4_v4_char(btheme->ttopbar.header, btheme->ttopbar.tab_inactive);
+			copy_v4_v4_char(btheme->ttopbar.back, tmp);
 		}
 	}
 
diff --git a/source/blender/editors/mesh/editmesh_tools.c b/source/blender/editors/mesh/editmesh_tools.c
index 5c2df386ef8..371f42e17b3 100644
--- a/source/blender/editors/mesh/editmesh_tools.c
+++ b/source/blender/editors/mesh/editmesh_tools.c
@@ -5584,7 +5584,7 @@ static void edbm_sort_elements_ui(bContext *C, wmOperator *op)
 	RNA_pointer_create(&wm->id, op->type->srna, op->properties, &ptr);
 
 	/* Main auto-draw call. */
-	uiDefAutoButsRNA(layout, &ptr, edbm_sort_elements_draw_check_prop, '\0');
+	uiDefAutoButsRNA(layout, &ptr, edbm_sort_elements_draw_check_prop, UI_BUT_LABEL_ALIGN_NONE, false);
 }
 
 void MESH_OT_sort_elements(wmOperatorType *ot)
diff --git a/source/blender/editors/object/object_data_transfer.c b/source/blender/editors/object/object_data_transfer.c
index 603f5b1c77f..d4e8955b38e 100644
--- a/source/blender/editors/object/object_data_transfer.c
+++ b/source/blender/editors/object/object_data_transfer.c
@@ -528,7 +528,7 @@ static void data_transfer_ui(bContext *C, wmOperator *op)
 	RNA_pointer_create(&wm->id, op->type->srna, op->properties, &ptr);
 
 	/* Main auto-draw call */
-	uiDefAutoButsRNA(layout, &ptr, data_transfer_draw_check_prop, '\0');
+	uiDefAutoButsRNA(layout, &ptr, data_transfer_draw_check_prop, UI_BUT_LABEL_ALIGN_NONE, false);
 }
 
 /* transfers weight from active to selected */
diff --git a/source/blender/editors/object/object_relations.c b/source/blender/editors/object/object_relations.c
index d2ac0f77c78..272478e46ff 100644
--- a/source/blender/editors/object/object_relations.c
+++ b/source/blender/editors/object/object_relations.c
@@ -972,7 +972,7 @@ static void parent_set_ui(bContext *C, wmOperator *op)
 	RNA_pointer_create(&wm->id, op->type->srna, op->properties, &ptr);
 
 	/* Main auto-draw call. */
-	uiDefAutoButsRNA(layout, &ptr, parent_set_draw_check_prop, '\0');
+	uiDefAutoButsRNA(layout, &ptr, parent_set_draw_check_prop, UI_BUT_LABEL_ALIGN_NONE, false);
 }
 
 void OBJECT_OT_parent_set(wmOperatorType *ot)
diff --git a/source/blender/editors/screen/area.c b/source/blender/editors/screen/area.c
index 105fff38f62..b6e2d2c57d4 100644
--- a/source/blender/editors/screen/area.c
+++ b/source/blender/editors/screen/area.c
@@ -1168,7 +1168,7 @@ static bool region_is_overlap(wmWindow *win, ScrArea *sa, ARegion *ar)
 	return 0;
 }
 
-static void region_rect_recursive(wmWindow *win, ScrArea *sa, ARegion *ar, rcti *remainder, int quad)
+static void region_rect_recursive(wmWindow *win, ScrArea *sa, ARegion *ar, rcti *remainder, int quad, bool add_azones)
 {
 	rcti *remainder_prev = remainder;
 	int prefsizex, prefsizey;
@@ -1195,13 +1195,17 @@ static void region_rect_recursive(wmWindow *win, ScrArea *sa, ARegion *ar, rcti
 	/* user errors */
 	if (ar->next == NULL && alignment != RGN_ALIGN_QSPLIT)
 		alignment = RGN_ALIGN_NONE;
-	
+
 	/* prefsize, for header we stick to exception (prevent dpi rounding error) */
-	prefsizex = UI_DPI_FAC * (ar->sizex > 1 ? ar->sizex + 0.5f : ar->type->prefsizex);
-	
+	const float sizex_dpi_fac = (ar->flag & RGN_SIZEX_DPI_APPLIED) ? 1.0f : UI_DPI_FAC;
+	prefsizex = sizex_dpi_fac * ((ar->sizex > 1) ? ar->sizex + 0.5f : ar->type->prefsizex);
+
 	if (ar->regiontype == RGN_TYPE_HEADER) {
 		prefsizey = ED_area_headersize();
 	}
+	else if (ED_area_is_global(sa)) {
+		prefsizey = ED_region_global_size_y();
+	}
 	else if (ar->regiontype == RGN_TYPE_UI && sa->spacetype == SPACE_FILE) {
 		prefsizey = UI_UNIT_Y * 2 + (UI_UNIT_Y / 2);
 	}
@@ -1397,7 +1401,7 @@ static void region_rect_recursive(wmWindow *win, ScrArea *sa, ARegion *ar, rcti
 		 * but accounts for small common rounding problems when scaling the UI,
 		 * must be minimum '4' */
 	}
-	else {
+	else if (add_azones) {
 		const bScreen *screen = WM_window_get_active_screen(win);
 
 		if (ELEM(screen->state, SCREENNORMAL, SCREENMAXIMIZED)) {
@@ -1409,23 +1413,36 @@ static void region_rect_recursive(wmWindow *win, ScrArea *sa, ARegion *ar, rcti
 		}
 	}
 
-	region_rect_recursive(win, sa, ar->next, remainder, quad);
+	region_rect_recursive(win, sa, ar->next, remainder, quad, add_azones);
 }
 
-static void area_calc_totrct(ScrArea *sa, int sizex, int sizey)
+static void area_calc_totrct(ScrArea *sa, int window_size_x, int window_size_y)
 {
-	short rt = (short) U.pixelsize;
+	short px = (short)U.pixelsize;
+
+	sa->totrct.xmin = sa->v1->vec.x;
+	sa->totrct.xmax = sa->v4->vec.x;
+	sa->totrct.ymin = sa->v1->vec.y;
+	sa->totrct.ymax = sa->v2->vec.y;
+
+	/* scale down totrct by 1 pixel on all sides not matching window borders */
+	if (sa->totrct.xmin > 0) {
+		sa->totrct.xmin += px;
+	}
+	if (sa->totrct.xmax < (window_size_x - 1)) {
+		sa->totrct.xmax -= px;
+	}
+	if (sa->totrct.ymin > 0) {
+		sa->totrct.ymin += px;
+	}
+	if (sa->totrct.ymax < (window_size_y - 1)) {
+		sa->totrct.ymax -= px;
+	}
+	BLI_assert(sa->totrct.xmin >= 0);
+	BLI_assert(sa->totrct.xmax >= 0);
+	BLI_assert(sa->totrct.ymin >= 0);
+	BLI_assert(sa->totrct.ymax >= 0);
 
-	if (sa->v1->vec.x > 0) sa->totrct.xmin = sa->v1->vec.x + rt;
-	else sa->totrct.xmin = sa->v1->vec.x;
-	if (sa->v4->vec.x < sizex - 1) sa->totrct.xmax = sa->v4->vec.x - rt;
-	else sa->totrct.xmax = sa->v4->vec.x;
-	
-	if (sa->v1->vec.y > 0) sa->totrct.ymin = sa->v1->vec.y + rt;
-	else sa->totrct.ymin = sa->v1->vec.y;
-	if (sa->v2->vec.y < sizey - 1) sa->totrct.ymax = sa->v2->vec.y - rt;
-	else sa->totrct.ymax = sa->v2->vec.y;
-	
 	/* for speedup */
 	sa->winx = BLI_rcti_size_x(&sa->totrct) + 1;
 	sa->winy = BLI_rcti_size_y(&sa->totrct) + 1;
@@ -1510,11 +1527,36 @@ static void ed_default_handlers(wmWindowManager *wm, ScrArea *sa, ListBase *hand
 	}
 }
 
+void screen_area_update_region_sizes(wmWindowManager *wm, wmWindow *win, ScrArea *area)
+{
+	const int size_x = WM_window_pixels_x(win);
+	const int size_y = WM_window_pixels_y(win);
+	rcti rect;
+
+	area_calc_totrct(area, size_x, size_y);
+
+	/* region rect sizes */
+	rect = area->totrct;
+	region_rect_recursive(win, area, area->regionbase.first, &rect, 0, false);
+
+	for (ARegion *ar = area->regionbase.first; ar; ar = ar->next) {
+		region_subwindow(ar);
+
+		/* region size may have changed, init does necessary adjustments */
+		if (ar->type->init) {
+			ar->type->init(wm, ar);
+		}
+	}
+
+	area->flag &= ~AREA_FLAG_REGION_SIZE_UPDATE;
+}
 
 /* called in screen_refresh, or screens_init, also area size changes */
 void ED_area_initialize(wmWindowManager *wm, wmWindow *win, ScrArea *sa)
 {
 	const bScreen *screen = WM_window_get_active_screen(win);
+	const int window_size_x = WM_window_pixels_x(win);
+	const int window_size_y = WM_window_pixels_y(win);
 	ARegion *ar;
 	rcti rect;
 	
@@ -1528,16 +1570,17 @@ void ED_area_initialize(wmWindowManager *wm, wmWindow *win, ScrArea *sa)
 	
 	for (ar = sa->regionbase.first; ar; ar = ar->next)
 		ar->type = BKE_regiontype_from_id(sa->type, ar->regiontype);
-	
+
 	/* area sizes */
-	area_calc_totrct(sa, WM_window_pixels_x(win), WM_window_pixels_y(win));
-	
+	area_calc_totrct(sa, window_size_x, window_size_y);
+
 	/* clear all azones, add the area triange widgets */
 	area_azone_initialize(win, screen, sa);
 
 	/* region rect sizes */
 	rect = sa->totrct;
-	region_rect_recursive(win, sa, sa->regionbase.first, &rect, 0);
+	region_rect_recursive(win, sa, sa->regionbase.first, &rect, 0, true);
+	sa->flag &= ~AREA_FLAG_REGION_SIZE_UPDATE;
 	
 	/* default area handlers */
 	ed_default_handlers(wm, sa, &sa->handlers, sa->type->keymapflag);
@@ -1832,6 +1875,18 @@ int ED_area_header_switchbutton(const bContext *C, uiBlock *block, int yco)
 
 /************************ standard UI regions ************************/
 
+static ThemeColorID region_background_color_id(const bContext *C, const ARegion *region)
+{
+	switch (region->regiontype) {
+		case RGN_TYPE_HEADER:
+			return ED_screen_area_active(C) ? TH_HEADER : TH_HEADERDESEL;
+		case RGN_TYPE_PREVIEW:
+			return TH_PREVIEW_BACK;
+		default:
+			return TH_BACK;
+	}
+}
+
 void ED_region_panels(const bContext *C, ARegion *ar, const char *context, int contextnr, const bool vertical)
 {
 	const WorkSpace *workspace = CTX_wm_workspace(C);
@@ -2117,17 +2172,25 @@ void ED_region_header(const bContext *C, ARegion *ar)
 	Header header = {NULL};
 	int maxco, xco, yco;
 	int headery = ED_area_headersize();
+	const int start_ofs = 0.4f * UI_UNIT_X;
+	bool region_layout_based = ar->flag & RGN_FLAG_DYNAMIC_SIZE;
 
 	/* clear */
-	UI_ThemeClearColor((ED_screen_area_active(C)) ? TH_HEADER : TH_HEADERDESEL);
+	UI_ThemeClearColor(region_background_color_id(C, ar));
 	glClear(GL_COLOR_BUFFER_BIT);
 	
 	/* set view2d view matrix for scrolling (without scrollers) */
 	UI_view2d_view_ortho(&ar->v2d);
 
-	xco = maxco = 0.4f * UI_UNIT_X;
+	xco = maxco = start_ofs;
 	yco = headery - floor(0.2f * UI_UNIT_Y);
 
+	/* XXX workaround for 1 px alignment issue. Not sure what causes it... Would prefer a proper fix - Julian */
+	if (CTX_wm_area(C)->spacetype == SPACE_TOPBAR) {
+		xco += 1;
+		yco += 1;
+	}
+
 	/* draw all headers types */
 	for (ht = ar->type->headertypes.first; ht; ht = ht->next) {
 		block = UI_block_begin(C, ar, ht->idname, UI_EMBOSS);
@@ -2149,13 +2212,23 @@ void ED_region_header(const bContext *C, ARegion *ar)
 		/* for view2d */
 		if (xco > maxco)
 			maxco = xco;
-		
+
+		if (region_layout_based && (ar->sizex != (maxco + start_ofs))) {
+			/* region size is layout based and needs to be updated */
+			ScrArea *sa = CTX_wm_area(C);
+
+			ar->sizex = maxco + start_ofs;
+			UI_view2d_region_reinit(&ar->v2d, V2D_COMMONVIEW_HEADER, ar->sizex, ar->winy);
+
+			sa->flag |= AREA_FLAG_REGION_SIZE_UPDATE;
+			ar->flag |= RGN_SIZEX_DPI_APPLIED;
+		}
 		UI_block_end(C, block);
 		UI_block_draw(C, block);
 	}
 
 	/* always as last  */
-	UI_view2d_totRect_set(&ar->v2d, maxco + UI_UNIT_X + 80, headery);
+	UI_view2d_totRect_set(&ar->v2d, maxco + (region_layout_based ? 0 : UI_UNIT_X + 80), headery);
 
 	/* restore view matrix? */
 	UI_view2d_view_restore(C);
@@ -2172,6 +2245,31 @@ int ED_area_headersize(void)
 	return (int)(HEADERY * UI_DPI_FAC);
 }
 
+/**
+ * \return the final height of a global \a area, accounting for DPI.
+ */
+int ED_area_global_size_y(const ScrArea *area)
+{
+	BLI_assert(ED_area_is_global(area));
+	return round_fl_to_int(area->global->cur_fixed_height * UI_DPI_FAC);
+}
+
+bool ED_area_is_global(const ScrArea *area)
+{
+	return area->global != NULL;
+}
+
+/**
+ * For now we just assume all global areas are made up out of horizontal bars
+ * with the same size. A fixed size could be stored in ARegion instead if needed.
+ *
+ * \return the DPI aware height of a single bar/region in global areas.
+ */
+int ED_region_global_size_y(void)
+{
+	return ED_area_headersize(); /* same size as header */
+}
+
 void ED_region_info_draw_multiline(ARegion *ar, const char *text_array[], float fill_color[4], const bool full_redraw)
 {
 	const int header_height = UI_UNIT_Y;
diff --git a/source/blender/editors/screen/screen_edit.c b/source/blender/editors/screen/screen_edit.c
index e961a7f5d64..82093b4326a 100644
--- a/source/blender/editors/screen/screen_edit.c
+++ b/source/blender/editors/screen/screen_edit.c
@@ -76,17 +76,21 @@
 
 /* ******************* screen vert, edge, area managing *********************** */
 
-static ScrVert *screen_addvert(bScreen *sc, short x, short y)
+static ScrVert *screen_addvert_ex(ScrAreaMap *area_map, short x, short y)
 {
 	ScrVert *sv = MEM_callocN(sizeof(ScrVert), "addscrvert");
 	sv->vec.x = x;
 	sv->vec.y = y;
 	
-	BLI_addtail(&sc->vertbase, sv);
+	BLI_addtail(&area_map->vertbase, sv);
 	return sv;
 }
+static ScrVert *screen_addvert(bScreen *sc, short x, short y)
+{
+	return screen_addvert_ex(AREAMAP_FROM_SCREEN(sc), x, y);
+}
 
-static ScrEdge *screen_addedge(bScreen *sc, ScrVert *v1, ScrVert *v2)
+static ScrEdge *screen_addedge_ex(ScrAreaMap *area_map, ScrVert *v1, ScrVert *v2)
 {
 	ScrEdge *se = MEM_callocN(sizeof(ScrEdge), "addscredge");
 
@@ -94,10 +98,13 @@ static ScrEdge *screen_addedge(bScreen *sc, ScrVert *v1, ScrVert *v2)
 	se->v1 = v1;
 	se->v2 = v2;
 
-	BLI_addtail(&sc->edgebase, se);
+	BLI_addtail(&area_map->edgebase, se);
 	return se;
 }
-
+static ScrEdge *screen_addedge(bScreen *sc, ScrVert *v1, ScrVert *v2)
+{
+	return screen_addedge_ex(AREAMAP_FROM_SCREEN(sc), v1, v2);
+}
 
 bool scredge_is_horizontal(ScrEdge *se)
 {
@@ -105,16 +112,16 @@ bool scredge_is_horizontal(ScrEdge *se)
 }
 
 /* need win size to make sure not to include edges along screen edge */
-ScrEdge *screen_find_active_scredge(const bScreen *sc,
-                                    const int winsize_x, const int winsize_y,
-                                    const int mx, const int my)
+ScrEdge *screen_area_map_find_active_scredge(
+        const ScrAreaMap *area_map,
+        const int winsize_x, const int winsize_y,
+        const int mx, const int my)
 {
-	ScrEdge *se;
 	int safety = U.widget_unit / 10;
-	
-	if (safety < 2) safety = 2;
-	
-	for (se = sc->edgebase.first; se; se = se->next) {
+
+	CLAMP_MIN(safety, 2);
+
+	for (ScrEdge *se = area_map->edgebase.first; se; se = se->next) {
 		if (scredge_is_horizontal(se)) {
 			if (se->v1->vec.y > 0 && se->v1->vec.y < winsize_y - 1) {
 				short min, max;
@@ -136,27 +143,56 @@ ScrEdge *screen_find_active_scredge(const bScreen *sc,
 			}
 		}
 	}
-	
+
 	return NULL;
 }
 
+/* need win size to make sure not to include edges along screen edge */
+ScrEdge *screen_find_active_scredge(
+        const wmWindow *win, const bScreen *screen,
+        const int mx, const int my)
+{
+	/* Use layout size (screen excluding global areas) for screen-layout area edges */
+	const int screen_x = WM_window_screen_pixels_x(win), screen_y = WM_window_screen_pixels_y(win);
+	ScrEdge *se = screen_area_map_find_active_scredge(AREAMAP_FROM_SCREEN(screen), screen_x, screen_y, mx, my);
+
+	if (!se) {
+		/* Use entire window size (screen including global areas) for global area edges */
+		const int win_x = WM_window_pixels_x(win), win_y = WM_window_pixels_y(win);
+		se = screen_area_map_find_active_scredge(&win->global_areas, win_x, win_y, mx, my);
+	}
+	return se;
+}
+
 
 
 /* adds no space data */
-static ScrArea *screen_addarea(bScreen *sc, ScrVert *v1, ScrVert *v2, ScrVert *v3, ScrVert *v4, short headertype, short spacetype)
+static ScrArea *screen_addarea_ex(
+        ScrAreaMap *area_map,
+        ScrVert *bottom_left, ScrVert *top_left, ScrVert *top_right, ScrVert *bottom_right,
+        short headertype, short spacetype)
 {
 	ScrArea *sa = MEM_callocN(sizeof(ScrArea), "addscrarea");
-	sa->v1 = v1;
-	sa->v2 = v2;
-	sa->v3 = v3;
-	sa->v4 = v4;
+
+	sa->v1 = bottom_left;
+	sa->v2 = top_left;
+	sa->v3 = top_right;
+	sa->v4 = bottom_right;
 	sa->headertype = headertype;
 	sa->spacetype = sa->butspacetype = spacetype;
-	
-	BLI_addtail(&sc->areabase, sa);
-	
+
+	BLI_addtail(&area_map->areabase, sa);
+
 	return sa;
 }
+static ScrArea *screen_addarea(
+        bScreen *sc,
+        ScrVert *left_bottom, ScrVert *left_top, ScrVert *right_top, ScrVert *right_bottom,
+        short headertype, short spacetype)
+{
+	return screen_addarea_ex(AREAMAP_FROM_SCREEN(sc), left_bottom, left_top, right_top, right_bottom,
+	                         headertype, spacetype);
+}
 
 static void screen_delarea(bContext *C, bScreen *sc, ScrArea *sa)
 {
@@ -462,10 +498,10 @@ int screen_area_join(bContext *C, bScreen *scr, ScrArea *sa1, ScrArea *sa2)
 	return 1;
 }
 
-void select_connected_scredge(bScreen *sc, ScrEdge *edge)
+void select_connected_scredge(const wmWindow *win, ScrEdge *edge)
 {
+	bScreen *sc = WM_window_get_active_screen(win);
 	ScrEdge *se;
-	ScrVert *sv;
 	int oneselected;
 	char dir;
 	
@@ -475,12 +511,10 @@ void select_connected_scredge(bScreen *sc, ScrEdge *edge)
 	if (edge->v1->vec.x == edge->v2->vec.x) dir = 'v';
 	else dir = 'h';
 	
-	sv = sc->vertbase.first;
-	while (sv) {
+	ED_screen_verts_iter(win, sc, sv) {
 		sv->flag = 0;
-		sv = sv->next;
 	}
-	
+
 	edge->v1->flag = 1;
 	edge->v2->flag = 1;
 	
@@ -508,8 +542,13 @@ void select_connected_scredge(bScreen *sc, ScrEdge *edge)
 	}
 }
 
-/* test if screen vertices should be scaled */
-static void screen_test_scale(bScreen *sc, int winsize_x, int winsize_y)
+/**
+ * Test if screen vertices should be scaled and do if needed.
+ */
+static void screen_vertices_scale(
+        const wmWindow *win, bScreen *sc,
+        int window_size_x, int window_size_y,
+        int screen_size_x, int screen_size_y)
 {
 	/* clamp Y size of header sized areas when expanding windows
 	 * avoids annoying empty space around file menu */
@@ -518,7 +557,7 @@ static void screen_test_scale(bScreen *sc, int winsize_x, int winsize_y)
 	const int headery_init = ED_area_headersize();
 	ScrVert *sv = NULL;
 	ScrArea *sa;
-	int winsize_x_prev, winsize_y_prev;
+	int screen_size_x_prev, screen_size_y_prev;
 	float facx, facy, tempf, min[2], max[2];
 	
 	/* calculate size */
@@ -536,8 +575,8 @@ static void screen_test_scale(bScreen *sc, int winsize_x, int winsize_y)
 		sv->vec.y -= min[1];
 	}
 	
-	winsize_x_prev = (max[0] - min[0]) + 1;
-	winsize_y_prev = (max[1] - min[1]) + 1;
+	screen_size_x_prev = (max[0] - min[0]) + 1;
+	screen_size_y_prev = (max[1] - min[1]) + 1;
 
 
 #ifdef USE_HEADER_SIZE_CLAMP
@@ -545,14 +584,14 @@ static void screen_test_scale(bScreen *sc, int winsize_x, int winsize_y)
 #define TEMP_TOP 2
 
 	/* if the window's Y axis grows, clamp header sized areas */
-	if (winsize_y_prev < winsize_y) {  /* growing? */
+	if (screen_size_y_prev < screen_size_y) {  /* growing? */
 		const int headery_margin_max = headery_init + 4;
 		for (sa = sc->areabase.first; sa; sa = sa->next) {
 			ARegion *ar = BKE_area_find_region_type(sa, RGN_TYPE_HEADER);
 			sa->temp = 0;
 
 			if (ar && !(ar->flag & RGN_FLAG_HIDDEN)) {
-				if (sa->v2->vec.y == winsize_y_prev - 1) {
+				if (sa->v2->vec.y == screen_size_y_prev) {
 					if ((sa->v2->vec.y - sa->v1->vec.y) < headery_margin_max) {
 						sa->temp = TEMP_TOP;
 					}
@@ -568,9 +607,9 @@ static void screen_test_scale(bScreen *sc, int winsize_x, int winsize_y)
 #endif
 
 
-	if (winsize_x_prev != winsize_x || winsize_y_prev != winsize_y) {
-		facx = ((float)winsize_x - 1) / ((float)winsize_x_prev - 1);
-		facy = ((float)winsize_y - 1) / ((float)winsize_y_prev - 1);
+	if (screen_size_x_prev != screen_size_x || screen_size_y_prev != screen_size_y) {
+		facx = ((float)screen_size_x - 1) / ((float)screen_size_x_prev - 1);
+		facy = ((float)screen_size_y) / ((float)screen_size_y_prev);
 		
 		/* make sure it fits! */
 		for (sv = sc->vertbase.first; sv; sv = sv->next) {
@@ -581,20 +620,20 @@ static void screen_test_scale(bScreen *sc, int winsize_x, int winsize_y)
 			//sv->vec.x += AREAGRID - 1;
 			//sv->vec.x -=  (sv->vec.x % AREAGRID);
 
-			CLAMP(sv->vec.x, 0, winsize_x - 1);
+			CLAMP(sv->vec.x, 0, screen_size_x - 1);
 			
 			tempf = ((float)sv->vec.y) * facy;
 			sv->vec.y = (short)(tempf + 0.5f);
 			//sv->vec.y += AREAGRID - 1;
 			//sv->vec.y -=  (sv->vec.y % AREAGRID);
 
-			CLAMP(sv->vec.y, 0, winsize_y - 1);
+			CLAMP(sv->vec.y, 0, screen_size_y);
 		}
 	}
 
 
 #ifdef USE_HEADER_SIZE_CLAMP
-	if (winsize_y_prev < winsize_y) {  /* growing? */
+	if (screen_size_y_prev < screen_size_y) {  /* growing? */
 		for (sa = sc->areabase.first; sa; sa = sa->next) {
 			ScrEdge *se = NULL;
 
@@ -610,7 +649,7 @@ static void screen_test_scale(bScreen *sc, int winsize_x, int winsize_y)
 				const int yval = sa->v2->vec.y - headery_init;
 				se = BKE_screen_find_edge(sc, sa->v4, sa->v1);
 				if (se != NULL) {
-					select_connected_scredge(sc, se);
+					select_connected_scredge(win, se);
 				}
 				for (sv = sc->vertbase.first; sv; sv = sv->next) {
 					if (sv != sa->v2 && sv != sa->v3) {
@@ -625,7 +664,7 @@ static void screen_test_scale(bScreen *sc, int winsize_x, int winsize_y)
 				const int yval = sa->v1->vec.y + headery_init;
 				se = BKE_screen_find_edge(sc, sa->v2, sa->v3);
 				if (se != NULL) {
-					select_connected_scredge(sc, se);
+					select_connected_scredge(win, se);
 				}
 				for (sv = sc->vertbase.first; sv; sv = sv->next) {
 					if (sv != sa->v1 && sv != sa->v4) {
@@ -654,7 +693,7 @@ static void screen_test_scale(bScreen *sc, int winsize_x, int winsize_y)
 		/* adjust headery if verts are along the edge of window */
 		if (sa->v1->vec.y > 0)
 			headery += U.pixelsize;
-		if (sa->v2->vec.y < winsize_y - 1)
+		if (sa->v2->vec.y < screen_size_y)
 			headery += U.pixelsize;
 		
 		if (sa->v2->vec.y - sa->v1->vec.y + 1 < headery) {
@@ -663,7 +702,7 @@ static void screen_test_scale(bScreen *sc, int winsize_x, int winsize_y)
 			if (se && sa->v1 != sa->v2) {
 				int yval;
 				
-				select_connected_scredge(sc, se);
+				select_connected_scredge(win, se);
 				
 				/* all selected vertices get the right offset */
 				yval = sa->v2->vec.y - headery + 1;
@@ -678,7 +717,17 @@ static void screen_test_scale(bScreen *sc, int winsize_x, int winsize_y)
 			}
 		}
 	}
-	
+
+	/* Global areas have a fixed size that only changes with the DPI. Here we ensure that exactly this size is set.
+	 * TODO Assumes global area to be top-aligned. Should be made more generic */
+	for (ScrArea *area = win->global_areas.areabase.first; area; area = area->next) {
+		/* width */
+		area->v1->vec.x = area->v2->vec.x = 0;
+		area->v3->vec.x = area->v4->vec.x = window_size_x - 1;
+		/* height */
+		area->v2->vec.y = area->v3->vec.y = window_size_y - 1;
+		area->v1->vec.y = area->v4->vec.y = area->v2->vec.y - ED_area_global_size_y(area);
+	}
 }
 
 
@@ -689,7 +738,7 @@ static void region_cursor_set(wmWindow *win, bool swin_changed)
 {
 	bScreen *screen = WM_window_get_active_screen(win);
 
-	for (ScrArea *sa = screen->areabase.first; sa; sa = sa->next) {
+	ED_screen_areas_iter(win, screen, sa) {
 		for (ARegion *ar = sa->regionbase.first; ar; ar = ar->next) {
 			if (ar == screen->active_region) {
 				if (swin_changed || (ar->type && ar->type->event_cursor)) {
@@ -751,20 +800,21 @@ void ED_screen_refresh(wmWindowManager *wm, wmWindow *win)
 
 	/* exception for bg mode, we only need the screen context */
 	if (!G.background) {
-		const int winsize_x = WM_window_pixels_x(win);
-		const int winsize_y = WM_window_pixels_y(win);
-		ScrArea *sa;
-		
+		const int window_size_x = WM_window_pixels_x(win);
+		const int window_size_y = WM_window_pixels_y(win);
+		const int screen_size_x = WM_window_screen_pixels_x(win);
+		const int screen_size_y = WM_window_screen_pixels_y(win);
+
 		/* header size depends on DPI, let's verify */
 		WM_window_set_dpi(win);
 		screen_refresh_headersizes();
-		
-		screen_test_scale(screen, winsize_x, winsize_y);
-		
-		for (sa = screen->areabase.first; sa; sa = sa->next) {
+
+		screen_vertices_scale(win, screen, window_size_x, window_size_y, screen_size_x, screen_size_y);
+
+		ED_screen_areas_iter(win, screen, area) {
 			/* set spacetype and region callbacks, calls init() */
 			/* sets subwindows for regions, adds handlers */
-			ED_area_initialize(wm, win, sa);
+			ED_area_initialize(wm, win, area);
 		}
 	
 		/* wake up animtimer */
@@ -782,6 +832,36 @@ void ED_screen_refresh(wmWindowManager *wm, wmWindow *win)
 	screen->context = ed_screen_context;
 }
 
+static bool screen_regions_need_size_refresh(
+        const wmWindow *win, const bScreen *screen)
+{
+	ED_screen_areas_iter(win, screen, area) {
+		if (area->flag & AREA_FLAG_REGION_SIZE_UPDATE) {
+			return true;
+		}
+	}
+
+	return false;
+}
+
+static void screen_refresh_region_sizes_only(
+        wmWindowManager *wm, wmWindow *win,
+        bScreen *screen)
+{
+	const int window_size_x = WM_window_pixels_x(win);
+	const int window_size_y = WM_window_pixels_y(win);
+	const int screen_size_x = WM_window_screen_pixels_x(win);
+	const int screen_size_y = WM_window_screen_pixels_y(win);
+
+	screen_vertices_scale(win, screen, window_size_x, window_size_y, screen_size_x, screen_size_y);
+
+	ED_screen_areas_iter(win, screen, area) {
+		screen_area_update_region_sizes(wm, win, area);
+		/* XXX hack to force drawing */
+		ED_area_tag_redraw(area);
+	}
+}
+
 /* file read, set all screens, ... */
 void ED_screens_initialize(wmWindowManager *wm)
 {
@@ -792,8 +872,21 @@ void ED_screens_initialize(wmWindowManager *wm)
 			WM_window_set_active_workspace(win, G.main->workspaces.first);
 		}
 
+		if (BLI_listbase_is_empty(&win->global_areas.areabase)) {
+			ED_screen_global_areas_create(win);
+		}
+		ED_screen_refresh(wm, win);
+	}
+}
+
+void ED_screen_ensure_updated(wmWindowManager *wm, wmWindow *win, bScreen *screen)
+{
+	if (screen->do_refresh) {
 		ED_screen_refresh(wm, win);
 	}
+	else if (screen_regions_need_size_refresh(win, screen)) {
+		screen_refresh_region_sizes_only(wm, win, screen);
+	}
 }
 
 
@@ -872,6 +965,9 @@ void ED_screen_exit(bContext *C, wmWindow *window, bScreen *screen)
 	for (sa = screen->areabase.first; sa; sa = sa->next) {
 		ED_area_exit(C, sa);
 	}
+	for (sa = window->global_areas.areabase.first; sa; sa = sa->next) {
+		ED_area_exit(C, sa);
+	}
 
 	/* mark it available for use for other windows */
 	screen->winid = 0;
@@ -893,9 +989,6 @@ void ED_screen_exit(bContext *C, wmWindow *window, bScreen *screen)
 static void screen_cursor_set(wmWindow *win, const wmEvent *event)
 {
 	const bScreen *screen = WM_window_get_active_screen(win);
-	const int winsize_x = WM_window_pixels_x(win);
-	const int winsize_y = WM_window_pixels_y(win);
-
 	AZone *az = NULL;
 	ScrArea *sa;
 	
@@ -914,8 +1007,8 @@ static void screen_cursor_set(wmWindow *win, const wmEvent *event)
 		}
 	}
 	else {
-		ScrEdge *actedge = screen_find_active_scredge(screen, winsize_x, winsize_y, event->x, event->y);
-		
+		ScrEdge *actedge = screen_find_active_scredge(win, screen, event->x, event->y);
+
 		if (actedge) {
 			if (scredge_is_horizontal(actedge))
 				WM_cursor_set(win, CURSOR_Y_MOVE);
@@ -936,15 +1029,19 @@ void ED_screen_set_active_region(bContext *C, const wmEvent *event)
 	bScreen *scr = WM_window_get_active_screen(win);
 
 	if (scr) {
-		ScrArea *sa;
+		ScrArea *sa = NULL;
 		ARegion *ar;
 		ARegion *old_ar = scr->active_region;
 
-		for (sa = scr->areabase.first; sa; sa = sa->next) {
-			if (event->x > sa->totrct.xmin && event->x < sa->totrct.xmax)
-				if (event->y > sa->totrct.ymin && event->y < sa->totrct.ymax)
-					if (NULL == is_in_area_actionzone(sa, &event->x))
+		ED_screen_areas_iter(win, scr, area_iter) {
+			if (event->x > area_iter->totrct.xmin && event->x < area_iter->totrct.xmax) {
+				if (event->y > area_iter->totrct.ymin && event->y < area_iter->totrct.ymax) {
+					if (is_in_area_actionzone(area_iter, &event->x) == NULL) {
+						sa = area_iter;
 						break;
+					}
+				}
+			}
 		}
 		if (sa) {
 			/* make overlap active when mouse over */
@@ -961,17 +1058,21 @@ void ED_screen_set_active_region(bContext *C, const wmEvent *event)
 		/* check for redraw headers */
 		if (old_ar != scr->active_region) {
 
-			for (sa = scr->areabase.first; sa; sa = sa->next) {
+			ED_screen_areas_iter(win, scr, area_iter) {
 				bool do_draw = false;
 				
-				for (ar = sa->regionbase.first; ar; ar = ar->next)
-					if (ar == old_ar || ar == scr->active_region)
+				for (ar = area_iter->regionbase.first; ar; ar = ar->next) {
+					if (ar == old_ar || ar == scr->active_region) {
 						do_draw = true;
+					}
+				}
 				
 				if (do_draw) {
-					for (ar = sa->regionbase.first; ar; ar = ar->next)
-						if (ar->regiontype == RGN_TYPE_HEADER)
+					for (ar = area_iter->regionbase.first; ar; ar = ar->next) {
+						if (ar->regiontype == RGN_TYPE_HEADER) {
 							ED_region_tag_redraw(ar);
+						}
+					}
 				}
 			}
 		}
@@ -1016,6 +1117,47 @@ int ED_screen_area_active(const bContext *C)
 	return 0;
 }
 
+void ED_screen_global_topbar_area_create(wmWindow *win, const bScreen *screen)
+{
+	if (screen->temp == 0) {
+		SpaceType *st = BKE_spacetype_from_id(SPACE_TOPBAR);
+		SpaceLink *sl = st->new(NULL);
+		ScrArea *sa;
+		const short size_y = 2 * HEADERY;
+		const int minx = 0, maxx = WM_window_pixels_x(win) - 1;
+		const int maxy = WM_window_pixels_y(win) - 1, miny = maxy - size_y;
+
+		ScrVert *bottom_left  = screen_addvert_ex(&win->global_areas, minx, miny);
+		ScrVert *top_left     = screen_addvert_ex(&win->global_areas, minx, maxy);
+		ScrVert *top_right    = screen_addvert_ex(&win->global_areas, maxx, maxy);
+		ScrVert *bottom_right = screen_addvert_ex(&win->global_areas, maxx, miny);
+		screen_addedge_ex(&win->global_areas, bottom_left, top_left);
+		screen_addedge_ex(&win->global_areas, top_left, top_right);
+		screen_addedge_ex(&win->global_areas, top_right, bottom_right);
+		screen_addedge_ex(&win->global_areas, bottom_right, bottom_left);
+
+		sa = screen_addarea_ex(&win->global_areas, bottom_left, top_left, top_right, bottom_right,
+		                       HEADERTOP, SPACE_TOPBAR);
+		sa->regionbase = sl->regionbase;
+
+		/* Data specific to global areas. */
+		sa->global = MEM_callocN(sizeof(*sa->global), __func__);
+		sa->global->cur_fixed_height = size_y;
+		sa->global->size_max = size_y;
+		sa->global->size_min = HEADERY;
+
+		BLI_addhead(&sa->spacedata, sl);
+		BLI_listbase_clear(&sl->regionbase);
+	}
+	/* Do not create more area types here! Function is called on file load (wm_window_ghostwindows_ensure). TODO */
+}
+
+void ED_screen_global_areas_create(wmWindow *win)
+{
+	const bScreen *screen = BKE_workspace_active_screen_get(win->workspace_hook);
+	ED_screen_global_topbar_area_create(win, screen);
+}
+
 
 /* -------------------------------------------------------------------- */
 /* Screen changing */
@@ -1168,7 +1310,6 @@ void ED_screen_update_after_scene_change(const bScreen *screen, Scene *scene_new
 ScrArea *ED_screen_full_newspace(bContext *C, ScrArea *sa, int type)
 {
 	wmWindow *win = CTX_wm_window(C);
-	bScreen *screen = CTX_wm_screen(C);
 	ScrArea *newsa = NULL;
 
 	if (!sa || sa->full == NULL) {
@@ -1176,18 +1317,7 @@ ScrArea *ED_screen_full_newspace(bContext *C, ScrArea *sa, int type)
 	}
 	
 	if (!newsa) {
-		if (sa->full && (screen->state == SCREENMAXIMIZED)) {
-			/* if this has been called from the temporary info header generated in
-			 * temp fullscreen layouts, find the correct fullscreen area to change
-			 * to create a new space inside */
-			for (newsa = screen->areabase.first; newsa; newsa = newsa->next) {
-				if (!(sa->flag & AREA_TEMP_INFO))
-					break;
-			}
-		}
-		else {
-			newsa = sa;
-		}
+		newsa = sa;
 	}
 
 	BLI_assert(newsa);
@@ -1308,10 +1438,8 @@ ScrArea *ED_screen_state_toggle(bContext *C, wmWindow *win, ScrArea *sa, const s
 
 			/* clear full screen state */
 			old->full = NULL;
-			old->flag &= ~AREA_TEMP_INFO;
 		}
 
-		sa->flag &= ~AREA_TEMP_INFO;
 		sa->full = NULL;
 
 		if (fullsa == NULL) {
@@ -1349,6 +1477,8 @@ ScrArea *ED_screen_state_toggle(bContext *C, wmWindow *win, ScrArea *sa, const s
 		ScrArea *newa;
 		char newname[MAX_ID_NAME - 2];
 
+		BLI_assert(ELEM(state, SCREENMAXIMIZED, SCREENFULL));
+
 		oldscreen = WM_window_get_active_screen(win);
 
 		oldscreen->state = state;
@@ -1367,50 +1497,30 @@ ScrArea *ED_screen_state_toggle(bContext *C, wmWindow *win, ScrArea *sa, const s
 
 		/* use random area when we have no active one, e.g. when the
 		 * mouse is outside of the window and we open a file browser */
-		if (!sa)
+		if (!sa) {
 			sa = oldscreen->areabase.first;
-
-		if (state == SCREENMAXIMIZED) {
-			/* returns the top small area */
-			newa = area_split(sc, (ScrArea *)sc->areabase.first, 'h', 0.99f, 1);
-			ED_area_newspace(C, newa, SPACE_INFO, false);
-
-			/* copy area */
-			newa = newa->prev;
-			ED_area_data_swap(newa, sa);
-			sa->flag |= AREA_TEMP_INFO;
-
-			sa->full = oldscreen;
-			newa->full = oldscreen;
-			newa->next->full = oldscreen; // XXX
 		}
-		else if (state == SCREENFULL) {
-			newa = (ScrArea *)sc->areabase.first;
 
-			/* copy area */
-			ED_area_data_swap(newa, sa);
-			newa->flag = sa->flag; /* mostly for AREA_FLAG_WASFULLSCREEN */
+		newa = (ScrArea *)sc->areabase.first;
+
+		/* copy area */
+		ED_area_data_swap(newa, sa);
+		newa->flag = sa->flag; /* mostly for AREA_FLAG_WASFULLSCREEN */
 
+		if (state == SCREENFULL) {
 			/* temporarily hide the side panels/header */
 			for (ar = newa->regionbase.first; ar; ar = ar->next) {
 				ar->flagfullscreen = ar->flag;
 
-				if (ELEM(ar->regiontype,
-				         RGN_TYPE_UI,
-				         RGN_TYPE_HEADER,
-				         RGN_TYPE_TOOLS))
-				{
+				if (ELEM(ar->regiontype, RGN_TYPE_UI, RGN_TYPE_HEADER, RGN_TYPE_TOOLS)){
 					ar->flag |= RGN_FLAG_HIDDEN;
 				}
 			}
-
-			sa->full = oldscreen;
-			newa->full = oldscreen;
-		}
-		else {
-			BLI_assert(false);
 		}
 
+		sa->full = oldscreen;
+		newa->full = oldscreen;
+
 		ED_screen_change(C, sc);
 	}
 
diff --git a/source/blender/editors/screen/screen_intern.h b/source/blender/editors/screen/screen_intern.h
index 606838ae890..045e5ee6b48 100644
--- a/source/blender/editors/screen/screen_intern.h
+++ b/source/blender/editors/screen/screen_intern.h
@@ -44,6 +44,7 @@ struct Main;
 /* area.c */
 void        ED_area_data_copy(ScrArea *sa_dst, ScrArea *sa_src, const bool do_free);
 void        ED_area_data_swap(ScrArea *sa1, ScrArea *sa2);
+void        screen_area_update_region_sizes(wmWindowManager *wm, wmWindow *win, ScrArea *area);
 void        region_toggle_hidden(struct bContext *C, ARegion *ar, const bool do_fade);
 
 /* screen_edit.c */
@@ -55,12 +56,16 @@ bScreen    *screen_change_prepare(bScreen *screen_old, bScreen *screen_new, stru
 ScrArea    *area_split(bScreen *sc, ScrArea *sa, char dir, float fac, int merge);
 int         screen_area_join(struct bContext *C, bScreen *scr, ScrArea *sa1, ScrArea *sa2);
 int         area_getorientation(ScrArea *sa, ScrArea *sb);
-void        select_connected_scredge(bScreen *sc, ScrEdge *edge);
+void        select_connected_scredge(const wmWindow *win, ScrEdge *edge);
 
 bool        scredge_is_horizontal(ScrEdge *se);
-ScrEdge    *screen_find_active_scredge(const bScreen *sc,
-                                       const int winsize_x, const int winsize_y,
-                                       const int mx, const int my);
+ScrEdge     *screen_area_map_find_active_scredge(
+        const struct ScrAreaMap *area_map,
+        const int winsize_x, const int winsize_y,
+        const int mx, const int my);
+ScrEdge    *screen_find_active_scredge(
+        const wmWindow *win, const bScreen *screen,
+        const int mx, const int my);
 
 struct AZone *is_in_area_actionzone(ScrArea *sa, const int xy[2]);
 
diff --git a/source/blender/editors/screen/screen_ops.c b/source/blender/editors/screen/screen_ops.c
index 25d5fbbdc4c..8b889c61deb 100644
--- a/source/blender/editors/screen/screen_ops.c
+++ b/source/blender/editors/screen/screen_ops.c
@@ -791,8 +791,8 @@ static int actionzone_modal(bContext *C, wmOperator *op, const wmEvent *event)
 	wmWindow *win = CTX_wm_window(C);
 	bScreen *sc = CTX_wm_screen(C);
 	sActionzoneData *sad = op->customdata;
-	const int winsize_x = WM_window_pixels_x(win);
-	const int winsize_y = WM_window_pixels_y(win);
+	const int screen_size_x = WM_window_screen_pixels_x(win);
+	const int screen_size_y = WM_window_screen_pixels_y(win);
 
 	switch (event->type) {
 		case MOUSEMOVE:
@@ -816,7 +816,8 @@ static int actionzone_modal(bContext *C, wmOperator *op, const wmEvent *event)
 				/* once we drag outside the actionzone, register a gesture
 				 * check we're not on an edge so join finds the other area */
 				is_gesture = ((is_in_area_actionzone(sad->sa1, &event->x) != sad->az) &&
-				              (screen_find_active_scredge(sc, winsize_x, winsize_y, event->x, event->y) == NULL));
+				              (screen_area_map_find_active_scredge(
+				                   AREAMAP_FROM_SCREEN(sc), screen_size_x, screen_size_y, event->x, event->y) == NULL));
 			}
 			else {
 				const int delta_min = 1;
@@ -1049,6 +1050,7 @@ static int area_dupli_invoke(bContext *C, wmOperator *op, const wmEvent *event)
 	layout_new = ED_workspace_layout_add(workspace, newwin, BKE_workspace_layout_name_get(layout_old));
 	newsc = BKE_workspace_layout_screen_get(layout_new);
 	WM_window_set_active_layout(newwin, workspace, layout_new);
+	ED_screen_global_areas_create(newwin);
 
 	/* copy area to new screen */
 	ED_area_data_copy((ScrArea *)newsc->areabase.first, sa, true);
@@ -1116,25 +1118,73 @@ static void SCREEN_OT_area_dupli(wmOperatorType *ot)
  */
 
 typedef struct sAreaMoveData {
-	int bigger, smaller, origval;
+	int bigger, smaller, origval, step;
 	char dir;
-	bool do_snap;
+	enum AreaMoveSnapType {
+		/* Snapping disabled */
+		SNAP_NONE = 0,
+		/* Snap to mid-point and adjacent edges. */
+		SNAP_MIDPOINT_AND_ADJACENT,
+		/* Snap to either bigger or smaller, nothing in-between (used for
+		 * global areas). This has priority over other snap types, if it is
+		 * used, toggling SNAP_MIDPOINT_AND_ADJACENT doesn't work. */
+		SNAP_BIGGER_SMALLER_ONLY,
+	} snap_type;
 } sAreaMoveData;
 
 /* helper call to move area-edge, sets limits
  * need window size in order to get correct limits */
-static void area_move_set_limits(bScreen *sc, int dir,
-                                 const int winsize_x, const int winsize_y,
-                                 int *bigger, int *smaller)
+static void area_move_set_limits(
+        wmWindow *win, bScreen *sc, int dir,
+        const int winsize_x, const int winsize_y,
+        int *bigger, int *smaller,
+        bool *use_bigger_smaller_snap)
 {
-	ScrArea *sa;
 	int areaminy = ED_area_headersize();
 	int areamin;
-	
+
 	/* we check all areas and test for free space with MINSIZE */
 	*bigger = *smaller = 100000;
-	
-	for (sa = sc->areabase.first; sa; sa = sa->next) {
+
+	if (use_bigger_smaller_snap != NULL) {
+		*use_bigger_smaller_snap = false;
+		for (ScrArea *area = win->global_areas.areabase.first; area; area = area->next) {
+			const int size_min = round_fl_to_int(area->global->size_min * UI_DPI_FAC);
+			const int size_max = round_fl_to_int(area->global->size_max * UI_DPI_FAC);
+
+			/* logic here is only tested for lower edge :) */
+			/* left edge */
+			if ((area->v1->editflag && area->v2->editflag)) {
+				*smaller = area->v4->vec.x - size_max;
+				*bigger  = area->v4->vec.x - size_min;
+				*use_bigger_smaller_snap = true;
+				return;
+			}
+			/* top edge */
+			else if ((area->v2->editflag && area->v3->editflag)) {
+				*smaller = area->v1->vec.y + size_min;
+				*bigger  = area->v1->vec.y + size_max;
+				*use_bigger_smaller_snap = true;
+				return;
+			}
+			/* right edge */
+			else if ((area->v3->editflag && area->v4->editflag)) {
+				*smaller = area->v1->vec.x + size_min;
+				*bigger  = area->v1->vec.x + size_max;
+				*use_bigger_smaller_snap = true;
+				return;
+			}
+			/* lower edge */
+			else if ((area->v4->editflag && area->v1->editflag)) {
+				*smaller = area->v2->vec.y - size_max;
+				*bigger  = area->v2->vec.y - size_min;
+				*use_bigger_smaller_snap = true;
+				return;
+			}
+		}
+	}
+
+	for (ScrArea *sa = sc->areabase.first; sa; sa = sa->next) {
 		if (dir == 'h') {
 			int y1;
 			areamin = areaminy;
@@ -1180,9 +1230,8 @@ static int area_move_init(bContext *C, wmOperator *op)
 	wmWindow *win = CTX_wm_window(C);
 	ScrEdge *actedge;
 	sAreaMoveData *md;
-	ScrVert *v1;
-	const int winsize_x = WM_window_pixels_x(win);
-	const int winsize_y = WM_window_pixels_y(win);
+	const int screen_size_x = WM_window_screen_pixels_x(win);
+	const int screen_size_y = WM_window_screen_pixels_y(win);
 	int x, y;
 	
 	/* required properties */
@@ -1190,7 +1239,7 @@ static int area_move_init(bContext *C, wmOperator *op)
 	y = RNA_int_get(op->ptr, "y");
 	
 	/* setup */
-	actedge = screen_find_active_scredge(sc, winsize_x, winsize_y, x, y);
+	actedge = screen_find_active_scredge(win, sc, x, y);
 	if (actedge == NULL) return 0;
 	
 	md = MEM_callocN(sizeof(sAreaMoveData), "sAreaMoveData");
@@ -1200,23 +1249,33 @@ static int area_move_init(bContext *C, wmOperator *op)
 	if (md->dir == 'h') md->origval = actedge->v1->vec.y;
 	else md->origval = actedge->v1->vec.x;
 	
-	select_connected_scredge(sc, actedge);
-	/* now all vertices with 'flag==1' are the ones that can be moved. Move this to editflag */
-	for (v1 = sc->vertbase.first; v1; v1 = v1->next)
+	select_connected_scredge(win, actedge);
+	/* now all vertices with 'flag == 1' are the ones that can be moved. Move this to editflag */
+	ED_screen_verts_iter(win, sc, v1) {
 		v1->editflag = v1->flag;
-	
-	area_move_set_limits(sc, md->dir, winsize_x, winsize_y, &md->bigger, &md->smaller);
-	
+	}
+
+	bool use_bigger_smaller_snap = false;
+	area_move_set_limits(win, sc, md->dir, screen_size_x, screen_size_y,
+	                     &md->bigger, &md->smaller,
+	                     &use_bigger_smaller_snap);
+
+	md->snap_type = use_bigger_smaller_snap ? SNAP_BIGGER_SMALLER_ONLY : SNAP_NONE;
+
 	return 1;
 }
 
 static int area_snap_calc_location(
-        const bScreen *sc, const int delta,
-        const int origval, const int dir,
+        const bScreen *sc, const enum AreaMoveSnapType snap_type,
+        const int delta, const int origval, const int dir,
         const int bigger, const int smaller)
 {
-	int final_loc = -1;
+	BLI_assert(snap_type != SNAP_NONE);
+	if (snap_type == SNAP_BIGGER_SMALLER_ONLY) {
+		return ((origval + delta) >= bigger) ? bigger : smaller;
+	}
 
+	int final_loc = -1;
 	const int m_loc = origval + delta;
 	const int axis = (dir == 'v') ? 0 : 1;
 	int snap_dist;
@@ -1260,29 +1319,29 @@ static void area_move_apply_do(
         const bContext *C, int delta,
         const int origval, const int dir,
         const int bigger, const int smaller,
-        const bool do_snap)
+        const enum AreaMoveSnapType snap_type)
 {
+	wmWindow *win = CTX_wm_window(C);
 	bScreen *sc = CTX_wm_screen(C);
-	ScrVert *v1;
 	bool doredraw = false;
 	CLAMP(delta, -smaller, bigger);
 
 	short final_loc = -1;
 
-	if (do_snap) {
-		final_loc = area_snap_calc_location(sc, delta, origval, dir, bigger, smaller);
-	}
-	else {
+	if (snap_type == SNAP_NONE) {
 		final_loc = origval + delta;
 		if (delta != bigger && delta != -smaller) {
 			final_loc -= (final_loc % AREAGRID);
 		}
 	}
+	else {
+		final_loc = area_snap_calc_location(sc, snap_type, delta, origval, dir, bigger, smaller);
+	}
 
 	BLI_assert(final_loc != -1);
 	short axis = (dir == 'v') ? 0 : 1;
 
-	for (v1 = sc->vertbase.first; v1; v1 = v1->next) {
+	ED_screen_verts_iter(win, sc, v1) {
 		if (v1->editflag) {
 			short oldval = (&v1->vec.x)[axis];
 			(&v1->vec.x)[axis] = final_loc;
@@ -1297,11 +1356,23 @@ static void area_move_apply_do(
 
 	/* only redraw if we actually moved a screen vert, for AREAGRID */
 	if (doredraw) {
-		for (ScrArea *sa = sc->areabase.first; sa; sa = sa->next) {
+		bool redraw_all = false;
+		ED_screen_areas_iter(win, sc, sa) {
 			if (sa->v1->editflag || sa->v2->editflag || sa->v3->editflag || sa->v4->editflag) {
+				if (ED_area_is_global(sa)) {
+					sa->global->cur_fixed_height = round_fl_to_int((sa->v2->vec.y - sa->v1->vec.y) / UI_DPI_FAC);
+					sc->do_refresh = true;
+					redraw_all = true;
+				}
 				ED_area_tag_redraw(sa);
 			}
 		}
+		if (redraw_all) {
+			ED_screen_areas_iter(win, sc, sa) {
+				ED_area_tag_redraw(sa);
+			}
+		}
+
 		WM_event_add_notifier(C, NC_SCREEN | NA_EDITED, NULL); /* redraw everything */
 		/* Update preview thumbnail */
 		BKE_icon_changed(sc->id.icon_id);
@@ -1313,7 +1384,7 @@ static void area_move_apply(bContext *C, wmOperator *op)
 	sAreaMoveData *md = op->customdata;
 	int delta = RNA_int_get(op->ptr, "delta");
 
-	area_move_apply_do(C, delta, md->origval, md->dir, md->bigger, md->smaller, md->do_snap);
+	area_move_apply_do(C, delta, md->origval, md->dir, md->bigger, md->smaller, md->snap_type);
 }
 
 static void area_move_exit(bContext *C, wmOperator *op)
@@ -1392,10 +1463,14 @@ static int area_move_modal(bContext *C, wmOperator *op, const wmEvent *event)
 					return OPERATOR_CANCELLED;
 
 				case KM_MODAL_SNAP_ON:
-					md->do_snap = true;
+					if (md->snap_type == SNAP_NONE) {
+						md->snap_type = SNAP_MIDPOINT_AND_ADJACENT;
+					}
 					break;
 				case KM_MODAL_SNAP_OFF:
-					md->do_snap = false;
+					if (md->snap_type == SNAP_MIDPOINT_AND_ADJACENT) {
+						md->snap_type = SNAP_NONE;
+					}
 					break;
 			}
 			break;
@@ -1644,8 +1719,8 @@ static int area_split_invoke(bContext *C, wmOperator *op, const wmEvent *event)
 	wmWindow *win = CTX_wm_window(C);
 	bScreen *sc = CTX_wm_screen(C);
 	sAreaSplitData *sd;
-	const int winsize_x = WM_window_pixels_x(win);
-	const int winsize_y = WM_window_pixels_y(win);
+	const int screen_size_x = WM_window_screen_pixels_x(win);
+	const int screen_size_y = WM_window_screen_pixels_y(win);
 	int dir;
 	
 	/* no full window splitting allowed */
@@ -1698,7 +1773,7 @@ static int area_split_invoke(bContext *C, wmOperator *op, const wmEvent *event)
 		else
 			y = event->x;
 		
-		actedge = screen_find_active_scredge(sc, winsize_x, winsize_y, x, y);
+		actedge = screen_area_map_find_active_scredge(AREAMAP_FROM_SCREEN(sc), screen_size_x, screen_size_y, x, y);
 		if (actedge == NULL)
 			return OPERATOR_CANCELLED;
 		
@@ -1718,7 +1793,7 @@ static int area_split_invoke(bContext *C, wmOperator *op, const wmEvent *event)
 		
 		/* do the split */
 		if (area_split_apply(C, op)) {
-			area_move_set_limits(sc, dir, winsize_x, winsize_y, &sd->bigger, &sd->smaller);
+			area_move_set_limits(win, sc, dir, screen_size_x, screen_size_y, &sd->bigger, &sd->smaller, NULL);
 			
 			/* add temp handler for edge move or cancel */
 			WM_event_add_modal_handler(C, op);
@@ -1836,10 +1911,11 @@ static int area_split_modal(bContext *C, wmOperator *op, const wmEvent *event)
 		if (sd->previewmode == 0) {
 			if (sd->do_snap) {
 				const int snap_loc = area_snap_calc_location(
-				        CTX_wm_screen(C), sd->delta, sd->origval, dir, sd->bigger, sd->smaller);
+				        CTX_wm_screen(C), SNAP_MIDPOINT_AND_ADJACENT, sd->delta, sd->origval, dir,
+				        sd->bigger, sd->smaller);
 				sd->delta = snap_loc - sd->origval;
 			}
-			area_move_apply_do(C, sd->delta, sd->origval, dir, sd->bigger, sd->smaller, false);
+			area_move_apply_do(C, sd->delta, sd->origval, dir, sd->bigger, sd->smaller, SNAP_NONE);
 		}
 		else {
 			if (sd->sarea) {
@@ -1863,7 +1939,8 @@ static int area_split_modal(bContext *C, wmOperator *op, const wmEvent *event)
 					sa->v1->editflag = sa->v2->editflag = sa->v3->editflag = sa->v4->editflag = 1;
 
 					const int snap_loc = area_snap_calc_location(
-					        CTX_wm_screen(C), sd->delta, sd->origval, dir, sd->origmin + sd->origsize, -sd->origmin);
+					        CTX_wm_screen(C), SNAP_MIDPOINT_AND_ADJACENT, sd->delta, sd->origval, dir,
+					        sd->origmin + sd->origsize, -sd->origmin);
 
 					sa->v1->editflag = sa->v2->editflag = sa->v3->editflag = sa->v4->editflag = 0;
 					sd->delta = snap_loc - sd->origval;
@@ -2579,6 +2656,14 @@ static int screen_maximize_area_exec(bContext *C, wmOperator *op)
 	return OPERATOR_FINISHED;
 }
 
+static int screen_maximize_area_poll(bContext *C)
+{
+	const bScreen *screen = CTX_wm_screen(C);
+	const ScrArea *area = CTX_wm_area(C);
+	return ED_operator_areaactive(C) &&
+	       ((screen->state != SCREENNORMAL) || (area->spacetype != SPACE_TOPBAR));
+}
+
 static void SCREEN_OT_screen_full_area(wmOperatorType *ot)
 {
 	PropertyRNA *prop;
@@ -2588,7 +2673,7 @@ static void SCREEN_OT_screen_full_area(wmOperatorType *ot)
 	ot->idname = "SCREEN_OT_screen_full_area";
 	
 	ot->exec = screen_maximize_area_exec;
-	ot->poll = ED_operator_areaactive;
+	ot->poll = screen_maximize_area_poll;
 	ot->flag = 0;
 
 	prop = RNA_def_boolean(ot->srna, "use_hide_panels", false, "Hide Panels", "Hide all the panels");
@@ -2898,10 +2983,11 @@ static int screen_area_options_invoke(bContext *C, wmOperator *op, const wmEvent
 	uiLayout *layout;
 	PointerRNA ptr;
 	ScrEdge *actedge;
-	const int winsize_x = WM_window_pixels_x(win);
-	const int winsize_y = WM_window_pixels_y(win);
+	const int screen_size_x = WM_window_screen_pixels_x(win);
+	const int screen_size_y = WM_window_screen_pixels_y(win);
 
-	actedge = screen_find_active_scredge(sc, winsize_x, winsize_y, event->x, event->y);
+	actedge = screen_area_map_find_active_scredge(
+	              AREAMAP_FROM_SCREEN(sc), screen_size_x, screen_size_y, event->x, event->y);
 	
 	if (actedge == NULL) return OPERATOR_CANCELLED;
 	
@@ -3305,6 +3391,18 @@ static int region_flip_exec(bContext *C, wmOperator *UNUSED(op))
 	return OPERATOR_FINISHED;
 }
 
+static int region_flip_poll(bContext *C)
+{
+	ScrArea *area = CTX_wm_area(C);
+
+	/* don't flip anything around in topbar */
+	if (area->spacetype == SPACE_TOPBAR) {
+		CTX_wm_operator_poll_msg_set(C, "Flipping regions in the Top-bar is not allowed");
+		return 0;
+	}
+
+	return ED_operator_areaactive(C);
+}
 
 static void SCREEN_OT_region_flip(wmOperatorType *ot)
 {
@@ -3315,7 +3413,7 @@ static void SCREEN_OT_region_flip(wmOperatorType *ot)
 	
 	/* api callbacks */
 	ot->exec = region_flip_exec;
-	ot->poll = ED_operator_areaactive;
+	ot->poll = region_flip_poll;
 	ot->flag = 0;
 }
 
@@ -3408,12 +3506,11 @@ void ED_screens_header_tools_menu_create(bContext *C, uiLayout *layout, void *UN
 
 	uiItemS(layout);
 
-	/* file browser should be fullscreen all the time, but other regions can be maximized/restored... */
-	if (sa->spacetype != SPACE_FILE) {
-		if (sa->full) 
-			uiItemO(layout, IFACE_("Tile Area"), ICON_NONE, "SCREEN_OT_screen_full_area");
-		else
-			uiItemO(layout, IFACE_("Maximize Area"), ICON_NONE, "SCREEN_OT_screen_full_area");
+	/* file browser should be fullscreen all the time, topbar should
+	 * never be. But other regions can be maximized/restored... */
+	if (!ELEM(sa->spacetype, SPACE_FILE, SPACE_TOPBAR)) {
+		const char *but_str = sa->full ? IFACE_("Tile Area") : IFACE_("Maximize Area");
+		uiItemO(layout, but_str, ICON_NONE, "SCREEN_OT_screen_full_area");
 	}
 }
 
diff --git a/source/blender/editors/screen/screendump.c b/source/blender/editors/screen/screendump.c
index 69891a727d4..2c1cbc3d21d 100644
--- a/source/blender/editors/screen/screendump.c
+++ b/source/blender/editors/screen/screendump.c
@@ -275,7 +275,7 @@ static void screenshot_draw(bContext *UNUSED(C), wmOperator *op)
 
 	/* main draw call */
 	RNA_pointer_create(NULL, op->type->srna, op->properties, &ptr);
-	uiDefAutoButsRNA(layout, &ptr, screenshot_draw_check_prop, '\0');
+	uiDefAutoButsRNA(layout, &ptr, screenshot_draw_check_prop, UI_BUT_LABEL_ALIGN_NONE, false);
 }
 
 static int screenshot_poll(bContext *C)
diff --git a/source/blender/editors/screen/workspace_edit.c b/source/blender/editors/screen/workspace_edit.c
index b40eef8a38f..c8aa4560dc4 100644
--- a/source/blender/editors/screen/workspace_edit.c
+++ b/source/blender/editors/screen/workspace_edit.c
@@ -313,11 +313,9 @@ static void WORKSPACE_OT_workspace_duplicate(wmOperatorType *ot)
 
 static int workspace_delete_exec(bContext *C, wmOperator *UNUSED(op))
 {
-	Main *bmain = CTX_data_main(C);
-	wmWindowManager *wm = CTX_wm_manager(C);
 	wmWindow *win = CTX_wm_window(C);
 
-	ED_workspace_delete(WM_window_get_active_workspace(win), bmain, C, wm);
+	WM_event_add_notifier(C, NC_SCREEN | ND_WORKSPACE_DELETE, WM_window_get_active_workspace(win));
 
 	return OPERATOR_FINISHED;
 }
diff --git a/source/blender/editors/screen/workspace_layout_edit.c b/source/blender/editors/screen/workspace_layout_edit.c
index d84df160125..a6f991d4bbe 100644
--- a/source/blender/editors/screen/workspace_layout_edit.c
+++ b/source/blender/editors/screen/workspace_layout_edit.c
@@ -50,10 +50,10 @@ WorkSpaceLayout *ED_workspace_layout_add(
         wmWindow *win,
         const char *name)
 {
-	const int winsize_x = WM_window_pixels_x(win);
-	const int winsize_y = WM_window_pixels_y(win);
+	const int screen_size_x = WM_window_screen_pixels_x(win);
+	const int screen_size_y = WM_window_screen_pixels_y(win);
 
-	bScreen *screen = screen_add(name, winsize_x, winsize_y);
+	bScreen *screen = screen_add(name, screen_size_x, screen_size_y);
 	WorkSpaceLayout *layout = BKE_workspace_layout_add(workspace, screen, name);
 
 	return layout;
diff --git a/source/blender/editors/sound/sound_ops.c b/source/blender/editors/sound/sound_ops.c
index a01b4aa1b18..eaf101b1083 100644
--- a/source/blender/editors/sound/sound_ops.c
+++ b/source/blender/editors/sound/sound_ops.c
@@ -635,7 +635,7 @@ static void sound_mixdown_draw(bContext *C, wmOperator *op)
 	RNA_pointer_create(&wm->id, op->type->srna, op->properties, &ptr);
 
 	/* main draw call */
-	uiDefAutoButsRNA(layout, &ptr, sound_mixdown_draw_check_prop, '\0');
+	uiDefAutoButsRNA(layout, &ptr, sound_mixdown_draw_check_prop, UI_BUT_LABEL_ALIGN_NONE, false);
 }
 #endif // WITH_AUDASPACE
 
diff --git a/source/blender/editors/space_api/spacetypes.c b/source/blender/editors/space_api/spacetypes.c
index fbdf543e5c4..ca9b87a5858 100644
--- a/source/blender/editors/space_api/spacetypes.c
+++ b/source/blender/editors/space_api/spacetypes.c
@@ -98,6 +98,7 @@ void ED_spacetypes_init(void)
 	ED_spacetype_console();
 	ED_spacetype_userpref();
 	ED_spacetype_clip();
+	ED_spacetype_topbar();
 //	...
 	
 	/* register operator types for screen and all spaces */
diff --git a/source/blender/editors/space_clip/clip_toolbar.c b/source/blender/editors/space_clip/clip_toolbar.c
index d2a7244eded..3b1f423b5ef 100644
--- a/source/blender/editors/space_clip/clip_toolbar.c
+++ b/source/blender/editors/space_clip/clip_toolbar.c
@@ -32,6 +32,7 @@
 #include <string.h>
 
 #include "DNA_windowmanager_types.h"
+#include "DNA_workspace_types.h"
 
 #include "MEM_guardedalloc.h"
 
@@ -118,19 +119,30 @@ void CLIP_OT_properties(wmOperatorType *ot)
 
 static ARegion *clip_has_tools_region(ScrArea *sa)
 {
-	ARegion *ar, *artool = NULL, *arprops = NULL, *arhead;
+	ARegion *ar, *artool = NULL, *arhead;
+#ifndef WITH_REDO_REGION_REMOVAL
+	ARegion *arprops = NULL;
+#endif
 
 	for (ar = sa->regionbase.first; ar; ar = ar->next) {
 		if (ar->regiontype == RGN_TYPE_TOOLS)
 			artool = ar;
 
+#ifndef WITH_REDO_REGION_REMOVAL
 		if (ar->regiontype == RGN_TYPE_TOOL_PROPS)
 			arprops = ar;
+#endif
 	}
 
 	/* tool region hide/unhide also hides props */
-	if (arprops && artool)
+	if (artool
+#ifndef WITH_REDO_REGION_REMOVAL
+	    && arprops
+#endif
+	    )
+	{
 		return artool;
+	}
 
 	if (artool == NULL) {
 		/* add subdiv level; after header */
@@ -149,6 +161,7 @@ static ARegion *clip_has_tools_region(ScrArea *sa)
 		artool->flag = RGN_FLAG_HIDDEN;
 	}
 
+#ifndef WITH_REDO_REGION_REMOVAL
 	if (arprops == NULL) {
 		/* add extra subdivided region for tool properties */
 		arprops = MEM_callocN(sizeof(ARegion), "tool props for clip");
@@ -157,6 +170,7 @@ static ARegion *clip_has_tools_region(ScrArea *sa)
 		arprops->regiontype = RGN_TYPE_TOOL_PROPS;
 		arprops->alignment = RGN_ALIGN_BOTTOM | RGN_SPLIT_PREV;
 	}
+#endif
 
 	return artool;
 }
@@ -189,11 +203,13 @@ void CLIP_OT_tools(wmOperatorType *ot)
 	ot->poll = tools_poll;
 }
 
+#ifndef WITH_REDO_REGION_REMOVAL
+
 /************************** redo panel ******************************/
 
 static void clip_panel_operator_redo_buts(const bContext *C, Panel *pa, wmOperator *op)
 {
-	uiTemplateOperatorPropertyButs(C, pa->layout, op, NULL, 'V', 0);
+	uiTemplateOperatorPropertyButs(C, pa->layout, op, NULL, UI_BUT_LABEL_ALIGN_COLUMN, 0);
 }
 
 static void clip_panel_operator_redo_header(const bContext *C, Panel *pa)
@@ -263,3 +279,4 @@ void ED_clip_tool_props_register(ARegionType *art)
 	pt->draw = clip_panel_operator_redo;
 	BLI_addtail(&art->paneltypes, pt);
 }
+#endif
diff --git a/source/blender/editors/space_clip/space_clip.c b/source/blender/editors/space_clip/space_clip.c
index 478254fb165..ba9684411b3 100644
--- a/source/blender/editors/space_clip/space_clip.c
+++ b/source/blender/editors/space_clip/space_clip.c
@@ -256,12 +256,14 @@ static SpaceLink *clip_new(const bContext *C)
 	ar->regiontype = RGN_TYPE_TOOLS;
 	ar->alignment = RGN_ALIGN_LEFT;
 
-	/* tool properties */
+#ifndef WITH_REDO_REGION_REMOVAL
+	/* tools view */
 	ar = MEM_callocN(sizeof(ARegion), "tool properties for clip");
 
 	BLI_addtail(&sc->regionbase, ar);
 	ar->regiontype = RGN_TYPE_TOOL_PROPS;
 	ar->alignment = RGN_ALIGN_BOTTOM | RGN_SPLIT_PREV;
+#endif
 
 	/* properties view */
 	ar = MEM_callocN(sizeof(ARegion), "properties for clip");
@@ -889,20 +891,25 @@ static void clip_refresh(const bContext *C, ScrArea *sa)
 	SpaceClip *sc = (SpaceClip *)sa->spacedata.first;
 	ARegion *ar_main = BKE_area_find_region_type(sa, RGN_TYPE_WINDOW);
 	ARegion *ar_tools = BKE_area_find_region_type(sa, RGN_TYPE_TOOLS);
-	ARegion *ar_tool_props = BKE_area_find_region_type(sa, RGN_TYPE_TOOL_PROPS);
 	ARegion *ar_preview = ED_clip_has_preview_region(C, sa);
 	ARegion *ar_properties = ED_clip_has_properties_region(sa);
 	ARegion *ar_channels = ED_clip_has_channels_region(sa);
 	bool main_visible = false, preview_visible = false, tools_visible = false;
-	bool tool_props_visible = false, properties_visible = false, channels_visible = false;
+	bool properties_visible = false, channels_visible = false;
 	bool view_changed = false;
+#ifndef WITH_REDO_REGION_REMOVAL
+	ARegion *ar_tool_props = BKE_area_find_region_type(sa, RGN_TYPE_TOOL_PROPS);
+	bool tool_props_visible = false;
+#endif
 
 	switch (sc->view) {
 		case SC_VIEW_CLIP:
 			main_visible = true;
 			preview_visible = false;
 			tools_visible = true;
+#ifndef WITH_REDO_REGION_REMOVAL
 			tool_props_visible = true;
+#endif
 			properties_visible = true;
 			channels_visible = false;
 			break;
@@ -910,7 +917,9 @@ static void clip_refresh(const bContext *C, ScrArea *sa)
 			main_visible = false;
 			preview_visible = true;
 			tools_visible = false;
+#ifndef WITH_REDO_REGION_REMOVAL
 			tool_props_visible = false;
+#endif
 			properties_visible = false;
 			channels_visible = false;
 
@@ -920,7 +929,9 @@ static void clip_refresh(const bContext *C, ScrArea *sa)
 			main_visible = false;
 			preview_visible = true;
 			tools_visible = false;
+#ifndef WITH_REDO_REGION_REMOVAL
 			tool_props_visible = false;
+#endif
 			properties_visible = false;
 			channels_visible = true;
 
@@ -1001,6 +1012,7 @@ static void clip_refresh(const bContext *C, ScrArea *sa)
 		}
 	}
 
+#ifndef WITH_REDO_REGION_REMOVAL
 	if (tool_props_visible) {
 		if (ar_tool_props && (ar_tool_props->flag & RGN_FLAG_HIDDEN)) {
 			ar_tool_props->flag &= ~RGN_FLAG_HIDDEN;
@@ -1024,6 +1036,7 @@ static void clip_refresh(const bContext *C, ScrArea *sa)
 			view_changed = true;
 		}
 	}
+#endif
 
 	if (preview_visible) {
 		if (ar_preview && (ar_preview->flag & RGN_FLAG_HIDDEN)) {
@@ -1607,6 +1620,7 @@ void ED_spacetype_clip(void)
 
 	BLI_addhead(&st->regiontypes, art);
 
+#ifndef WITH_REDO_REGION_REMOVAL
 	/* tool properties */
 	art = MEM_callocN(sizeof(ARegionType), "spacetype clip tool properties region");
 	art->regionid = RGN_TYPE_TOOL_PROPS;
@@ -1619,6 +1633,7 @@ void ED_spacetype_clip(void)
 	ED_clip_tool_props_register(art);
 
 	BLI_addhead(&st->regiontypes, art);
+#endif
 
 	/* regions: header */
 	art = MEM_callocN(sizeof(ARegionType), "spacetype clip region");
diff --git a/source/blender/editors/space_file/file_panels.c b/source/blender/editors/space_file/file_panels.c
index 1839e861518..363e9666399 100644
--- a/source/blender/editors/space_file/file_panels.c
+++ b/source/blender/editors/space_file/file_panels.c
@@ -88,7 +88,8 @@ static void file_panel_operator(const bContext *C, Panel *pa)
 
 	UI_block_func_set(uiLayoutGetBlock(pa->layout), file_draw_check_cb, NULL, NULL);
 
-	uiTemplateOperatorPropertyButs(C, pa->layout, op, file_panel_check_prop, '\0', UI_TEMPLATE_OP_PROPS_SHOW_EMPTY);
+	uiTemplateOperatorPropertyButs(C, pa->layout, op, file_panel_check_prop, UI_BUT_LABEL_ALIGN_NONE,
+	                               UI_TEMPLATE_OP_PROPS_SHOW_EMPTY);
 
 	UI_block_func_set(uiLayoutGetBlock(pa->layout), NULL, NULL, NULL);
 }
diff --git a/source/blender/editors/space_image/image_ops.c b/source/blender/editors/space_image/image_ops.c
index a905e61dd88..a2afb5cb5c5 100644
--- a/source/blender/editors/space_image/image_ops.c
+++ b/source/blender/editors/space_image/image_ops.c
@@ -1431,7 +1431,7 @@ static void image_open_draw(bContext *UNUSED(C), wmOperator *op)
 
 	/* main draw call */
 	RNA_pointer_create(NULL, op->type->srna, op->properties, &ptr);
-	uiDefAutoButsRNA(layout, &ptr, image_open_draw_check_prop, '\0');
+	uiDefAutoButsRNA(layout, &ptr, image_open_draw_check_prop, UI_BUT_LABEL_ALIGN_NONE, false);
 
 	/* image template */
 	RNA_pointer_create(NULL, &RNA_ImageFormatSettings, imf, &imf_ptr);
@@ -2147,7 +2147,7 @@ static void image_save_as_draw(bContext *UNUSED(C), wmOperator *op)
 
 	/* main draw call */
 	RNA_pointer_create(NULL, op->type->srna, op->properties, &ptr);
-	uiDefAutoButsRNA(layout, &ptr, image_save_as_draw_check_prop, '\0');
+	uiDefAutoButsRNA(layout, &ptr, image_save_as_draw_check_prop, UI_BUT_LABEL_ALIGN_NONE, false);
 
 	/* multiview template */
 	if (is_multiview)
diff --git a/source/blender/editors/space_sequencer/sequencer_add.c b/source/blender/editors/space_sequencer/sequencer_add.c
index 0b6bacfbe68..caa3ba593fb 100644
--- a/source/blender/editors/space_sequencer/sequencer_add.c
+++ b/source/blender/editors/space_sequencer/sequencer_add.c
@@ -690,7 +690,7 @@ static void sequencer_add_draw(bContext *UNUSED(C), wmOperator *op)
 
 	/* main draw call */
 	RNA_pointer_create(NULL, op->type->srna, op->properties, &ptr);
-	uiDefAutoButsRNA(layout, &ptr, sequencer_add_draw_check_prop, '\0');
+	uiDefAutoButsRNA(layout, &ptr, sequencer_add_draw_check_prop, UI_BUT_LABEL_ALIGN_NONE, false);
 
 	/* image template */
 	RNA_pointer_create(NULL, &RNA_ImageFormatSettings, imf, &imf_ptr);
diff --git a/source/blender/editors/space_topbar/CMakeLists.txt b/source/blender/editors/space_topbar/CMakeLists.txt
new file mode 100644
index 00000000000..9559c28de0a
--- /dev/null
+++ b/source/blender/editors/space_topbar/CMakeLists.txt
@@ -0,0 +1,45 @@
+# ***** BEGIN GPL LICENSE BLOCK *****
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software Foundation,
+# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+#
+# Contributor(s): Jacques Beaurain.
+#
+# ***** END GPL LICENSE BLOCK *****
+
+set(INC
+	../include
+	../../blenkernel
+	../../blenlib
+	../../blenloader
+	../../blentranslation
+	../../gpu
+	../../makesdna
+	../../makesrna
+	../../windowmanager
+	../../../../intern/guardedalloc
+	../../../../intern/glew-mx
+)
+
+set(INC_SYS
+	${GLEW_INCLUDE_PATH}
+)
+
+set(SRC
+	space_topbar.c
+)
+
+add_definitions(${GL_DEFINITIONS})
+
+blender_add_lib(bf_editor_space_topbar "${SRC}" "${INC}" "${INC_SYS}")
diff --git a/source/blender/editors/space_topbar/space_topbar.c b/source/blender/editors/space_topbar/space_topbar.c
new file mode 100644
index 00000000000..35858a927fe
--- /dev/null
+++ b/source/blender/editors/space_topbar/space_topbar.c
@@ -0,0 +1,265 @@
+/*
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * The Original Code is Copyright (C) 2017 Blender Foundation.
+ * All rights reserved.
+ *
+ * Contributor(s): Blender Foundation
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+/** \file blender/editors/space_topbar/space_topbar.c
+ *  \ingroup sptopbar
+ */
+
+
+#include <string.h>
+#include <stdio.h>
+
+#include "MEM_guardedalloc.h"
+
+#include "BLI_blenlib.h"
+#include "BLI_utildefines.h"
+
+#include "BLO_readfile.h"
+#include "BLT_translation.h"
+
+#include "BKE_context.h"
+#include "BKE_global.h"
+#include "BKE_screen.h"
+
+#include "ED_screen.h"
+#include "ED_space_api.h"
+
+#include "UI_interface.h"
+#include "UI_resources.h"
+#include "UI_view2d.h"
+
+#include "WM_api.h"
+#include "WM_types.h"
+
+
+/* ******************** default callbacks for topbar space ***************** */
+
+static SpaceLink *topbar_new(const bContext *UNUSED(C))
+{
+	ARegion *ar;
+	SpaceTopBar *stopbar;
+
+	stopbar = MEM_callocN(sizeof(*stopbar), "init topbar");
+	stopbar->spacetype = SPACE_TOPBAR;
+
+	/* header */
+	ar = MEM_callocN(sizeof(ARegion), "left aligned header for topbar");
+	BLI_addtail(&stopbar->regionbase, ar);
+	ar->regiontype = RGN_TYPE_HEADER;
+	ar->alignment = RGN_ALIGN_TOP;
+	ar = MEM_callocN(sizeof(ARegion), "right aligned header for topbar");
+	BLI_addtail(&stopbar->regionbase, ar);
+	ar->regiontype = RGN_TYPE_HEADER;
+	ar->alignment = RGN_ALIGN_RIGHT | RGN_SPLIT_PREV;
+
+	/* main regions */
+	ar = MEM_callocN(sizeof(ARegion), "left aligned main region for topbar");
+	BLI_addtail(&stopbar->regionbase, ar);
+	ar->regiontype = RGN_TYPE_WINDOW;
+	ar->alignment = RGN_ALIGN_LEFT;
+	ar = MEM_callocN(sizeof(ARegion), "right aligned main region for topbar");
+	BLI_addtail(&stopbar->regionbase, ar);
+	ar->regiontype = RGN_TYPE_WINDOW;
+	ar->alignment = RGN_ALIGN_RIGHT;
+	ar = MEM_callocN(sizeof(ARegion), "center main region for topbar");
+	BLI_addtail(&stopbar->regionbase, ar);
+	ar->regiontype = RGN_TYPE_WINDOW;
+
+	return (SpaceLink *)stopbar;
+}
+
+/* not spacelink itself */
+static void topbar_free(SpaceLink *UNUSED(sl))
+{
+	
+}
+
+
+/* spacetype; init callback */
+static void topbar_init(struct wmWindowManager *UNUSED(wm), ScrArea *UNUSED(sa))
+{
+	
+}
+
+static SpaceLink *topbar_duplicate(SpaceLink *sl)
+{
+	SpaceTopBar *stopbarn = MEM_dupallocN(sl);
+
+	/* clear or remove stuff from old */
+
+	return (SpaceLink *)stopbarn;
+}
+
+
+
+/* add handlers, stuff you only do once or on area/region changes */
+static void topbar_main_region_init(wmWindowManager *wm, ARegion *region)
+{
+	wmKeyMap *keymap;
+
+	/* force delayed UI_view2d_region_reinit call */
+	if (ELEM(region->alignment, RGN_ALIGN_LEFT, RGN_ALIGN_RIGHT)) {
+		region->flag |= RGN_FLAG_DYNAMIC_SIZE;
+	}
+	UI_view2d_region_reinit(&region->v2d, V2D_COMMONVIEW_HEADER, region->winx, region->winy);
+
+	keymap = WM_keymap_find(wm->defaultconf, "View2D Buttons List", 0, 0);
+	WM_event_add_keymap_handler(&region->handlers, keymap);
+}
+
+static void topbar_main_region_draw(const bContext *C, ARegion *region)
+{
+	ED_region_header(C, region);
+}
+
+static void topbar_operatortypes(void)
+{
+	
+}
+
+static void topbar_keymap(struct wmKeyConfig *UNUSED(keyconf))
+{
+	
+}
+
+/* add handlers, stuff you only do once or on area/region changes */
+static void topbar_header_region_init(wmWindowManager *UNUSED(wm), ARegion *ar)
+{
+	if ((ar->alignment & ~RGN_SPLIT_PREV) == RGN_ALIGN_RIGHT) {
+		ar->flag |= RGN_FLAG_DYNAMIC_SIZE;
+	}
+	ED_region_header_init(ar);
+}
+
+static void topbar_header_region_draw(const bContext *C, ARegion *ar)
+{
+	ED_region_header(C, ar);
+}
+
+static void topbar_main_region_listener(bScreen *UNUSED(sc), ScrArea *UNUSED(sa), ARegion *ar,
+                                        wmNotifier *wmn, const Scene *UNUSED(scene))
+{
+	/* context changes */
+	switch (wmn->category) {
+		case NC_WM:
+			if (wmn->data == ND_HISTORY)
+				ED_region_tag_redraw(ar);
+			break;
+		case NC_SCENE:
+			if (wmn->data == ND_MODE)
+				ED_region_tag_redraw(ar);
+			break;
+		case NC_SPACE:
+			if (wmn->data == ND_SPACE_VIEW3D)
+				ED_region_tag_redraw(ar);
+			break;
+	}
+}
+
+static void topbar_header_listener(bScreen *UNUSED(sc), ScrArea *UNUSED(sa), ARegion *UNUSED(ar),
+                                   wmNotifier *UNUSED(wmn), const Scene *UNUSED(scene))
+{
+	/* context changes */
+#if 0
+	switch (wmn->category) {
+		default:
+			break;
+	}
+#endif
+}
+
+static void recent_files_menu_draw(const bContext *UNUSED(C), Menu *menu)
+{
+	struct RecentFile *recent;
+	uiLayout *layout = menu->layout;
+	uiLayoutSetOperatorContext(layout, WM_OP_EXEC_REGION_WIN);
+	if (!BLI_listbase_is_empty(&G.recent_files)) {
+		for (recent = G.recent_files.first; (recent); recent = recent->next) {
+			const char *file = BLI_path_basename(recent->filepath);
+			const int icon = BLO_has_bfile_extension(file) ? ICON_FILE_BLEND : ICON_FILE_BACKUP;
+			uiItemStringO(layout, file, icon, "WM_OT_open_mainfile", "filepath", recent->filepath);
+		}
+	}
+	else {
+		uiItemL(layout, IFACE_("No Recent Files"), ICON_NONE);
+	}
+}
+
+static void recent_files_menu_register(void)
+{
+	MenuType *mt;
+
+	mt = MEM_callocN(sizeof(MenuType), "spacetype info menu recent files");
+	strcpy(mt->idname, "TOPBAR_MT_file_open_recent");
+	strcpy(mt->label, N_("Open Recent..."));
+	strcpy(mt->translation_context, BLT_I18NCONTEXT_DEFAULT_BPYRNA);
+	mt->draw = recent_files_menu_draw;
+	WM_menutype_add(mt);
+}
+
+
+/* only called once, from space/spacetypes.c */
+void ED_spacetype_topbar(void)
+{
+	SpaceType *st = MEM_callocN(sizeof(SpaceType), "spacetype topbar");
+	ARegionType *art;
+
+	st->spaceid = SPACE_TOPBAR;
+	strncpy(st->name, "Top Bar", BKE_ST_MAXNAME);
+
+	st->new = topbar_new;
+	st->free = topbar_free;
+	st->init = topbar_init;
+	st->duplicate = topbar_duplicate;
+	st->operatortypes = topbar_operatortypes;
+	st->keymap = topbar_keymap;
+
+	/* regions: main window */
+	art = MEM_callocN(sizeof(ARegionType), "spacetype topbar main region");
+	art->regionid = RGN_TYPE_WINDOW;
+	art->init = topbar_main_region_init;
+	art->draw = topbar_main_region_draw;
+	art->listener = topbar_main_region_listener;
+	art->prefsizex = UI_UNIT_X * 5; /* Mainly to avoid glitches */
+	art->keymapflag = ED_KEYMAP_UI | ED_KEYMAP_VIEW2D | ED_KEYMAP_HEADER;
+
+	BLI_addhead(&st->regiontypes, art);
+
+	/* regions: header */
+	art = MEM_callocN(sizeof(ARegionType), "spacetype topbar header region");
+	art->regionid = RGN_TYPE_HEADER;
+	art->prefsizey = HEADERY;
+	art->prefsizex = UI_UNIT_X * 5; /* Mainly to avoid glitches */
+	art->keymapflag = ED_KEYMAP_UI | ED_KEYMAP_VIEW2D | ED_KEYMAP_HEADER;
+	art->listener = topbar_header_listener;
+	art->init = topbar_header_region_init;
+	art->draw = topbar_header_region_draw;
+
+	BLI_addhead(&st->regiontypes, art);
+
+	recent_files_menu_register();
+
+	BKE_spacetype_register(st);
+}
diff --git a/source/blender/editors/space_view3d/space_view3d.c b/source/blender/editors/space_view3d/space_view3d.c
index a87154ea049..8ee3f185c49 100644
--- a/source/blender/editors/space_view3d/space_view3d.c
+++ b/source/blender/editors/space_view3d/space_view3d.c
@@ -113,18 +113,30 @@ ARegion *view3d_has_buttons_region(ScrArea *sa)
 
 ARegion *view3d_has_tools_region(ScrArea *sa)
 {
-	ARegion *ar, *artool = NULL, *arprops = NULL, *arhead;
-	
+	ARegion *ar, *artool = NULL, *arhead;
+#ifndef WITH_REDO_REGION_REMOVAL
+	ARegion *arprops = NULL;
+#endif
+
 	for (ar = sa->regionbase.first; ar; ar = ar->next) {
 		if (ar->regiontype == RGN_TYPE_TOOLS)
 			artool = ar;
+#ifndef WITH_REDO_REGION_REMOVAL
 		if (ar->regiontype == RGN_TYPE_TOOL_PROPS)
 			arprops = ar;
+#endif
 	}
-	
+
 	/* tool region hide/unhide also hides props */
-	if (arprops && artool) return artool;
-	
+	if (artool
+#ifndef WITH_REDO_REGION_REMOVAL
+	    && arprops
+#endif
+	    )
+	{
+		return artool;
+	}
+
 	if (artool == NULL) {
 		/* add subdiv level; after header */
 		for (arhead = sa->regionbase.first; arhead; arhead = arhead->next)
@@ -142,15 +154,17 @@ ARegion *view3d_has_tools_region(ScrArea *sa)
 		artool->flag = RGN_FLAG_HIDDEN;
 	}
 
+#ifndef WITH_REDO_REGION_REMOVAL
 	if (arprops == NULL) {
 		/* add extra subdivided region for tool properties */
 		arprops = MEM_callocN(sizeof(ARegion), "tool props for view3d");
-		
+
 		BLI_insertlinkafter(&sa->regionbase, artool, arprops);
 		arprops->regiontype = RGN_TYPE_TOOL_PROPS;
 		arprops->alignment = RGN_ALIGN_BOTTOM | RGN_SPLIT_PREV;
 	}
-	
+#endif
+
 	return artool;
 }
 
@@ -369,15 +383,17 @@ static SpaceLink *view3d_new(const bContext *C)
 	ar->regiontype = RGN_TYPE_TOOLS;
 	ar->alignment = RGN_ALIGN_LEFT;
 	ar->flag = RGN_FLAG_HIDDEN;
-	
+
+#ifndef WITH_REDO_REGION_REMOVAL
 	/* tool properties */
 	ar = MEM_callocN(sizeof(ARegion), "tool properties for view3d");
-	
+
 	BLI_addtail(&v3d->regionbase, ar);
 	ar->regiontype = RGN_TYPE_TOOL_PROPS;
 	ar->alignment = RGN_ALIGN_BOTTOM | RGN_SPLIT_PREV;
 	ar->flag = RGN_FLAG_HIDDEN;
-	
+#endif
+
 	/* buttons/list view */
 	ar = MEM_callocN(sizeof(ARegion), "buttons for view3d");
 	
@@ -1312,6 +1328,7 @@ static void view3d_tools_region_draw(const bContext *C, ARegion *ar)
 	ED_region_panels(C, ar, CTX_data_mode_string(C), -1, true);
 }
 
+#ifndef WITH_REDO_REGION_REMOVAL
 static void view3d_props_region_listener(
         bScreen *UNUSED(sc), ScrArea *UNUSED(sa), ARegion *ar,
         wmNotifier *wmn, const Scene *UNUSED(scene))
@@ -1332,6 +1349,7 @@ static void view3d_props_region_listener(
 			break;
 	}
 }
+#endif
 
 /* area (not region) level listener */
 static void space_view3d_listener(
@@ -1523,6 +1541,7 @@ void ED_spacetype_view3d(void)
 	view3d_toolshelf_register(art);
 #endif
 
+#ifndef WITH_REDO_REGION_REMOVAL
 	/* regions: tool properties */
 	art = MEM_callocN(sizeof(ARegionType), "spacetype view3d tool properties region");
 	art->regionid = RGN_TYPE_TOOL_PROPS;
@@ -1533,10 +1552,10 @@ void ED_spacetype_view3d(void)
 	art->init = view3d_tools_region_init;
 	art->draw = view3d_tools_region_draw;
 	BLI_addhead(&st->regiontypes, art);
-	
+
 	view3d_tool_props_register(art);
-	
-	
+#endif
+
 	/* regions: header */
 	art = MEM_callocN(sizeof(ARegionType), "spacetype view3d header region");
 	art->regionid = RGN_TYPE_HEADER;
diff --git a/source/blender/editors/space_view3d/view3d_toolbar.c b/source/blender/editors/space_view3d/view3d_toolbar.c
index dfa64bd2015..8c77cf36c91 100644
--- a/source/blender/editors/space_view3d/view3d_toolbar.c
+++ b/source/blender/editors/space_view3d/view3d_toolbar.c
@@ -63,11 +63,12 @@
 #include "view3d_intern.h"  /* own include */
 
 
+#ifndef WITH_REDO_REGION_REMOVAL
 /* ******************* view3d space & buttons ************** */
 
 static void view3d_panel_operator_redo_buts(const bContext *C, Panel *pa, wmOperator *op)
 {
-	uiTemplateOperatorPropertyButs(C, pa->layout, op, NULL, 'V', 0);
+	uiTemplateOperatorPropertyButs(C, pa->layout, op, NULL, UI_BUT_LABEL_ALIGN_COLUMN, 0);
 }
 
 static void view3d_panel_operator_redo_header(const bContext *C, Panel *pa)
@@ -126,6 +127,8 @@ static void view3d_panel_operator_redo(const bContext *C, Panel *pa)
 	CTX_wm_region_set((bContext *)C, ar);
 }
 
+#endif
+
 /* ******************* */
 
 typedef struct CustomTool {
@@ -239,10 +242,11 @@ void view3d_toolshelf_register(ARegionType *art)
 	BLI_addtail(&art->paneltypes, pt);
 }
 
+#ifndef WITH_REDO_REGION_REMOVAL
 void view3d_tool_props_register(ARegionType *art)
 {
 	PanelType *pt;
-	
+
 	pt = MEM_callocN(sizeof(PanelType), "spacetype view3d panel last operator");
 	strcpy(pt->idname, "VIEW3D_PT_last_operator");
 	strcpy(pt->label, N_("Operator"));
@@ -251,6 +255,7 @@ void view3d_tool_props_register(ARegionType *art)
 	pt->draw = view3d_panel_operator_redo;
 	BLI_addtail(&art->paneltypes, pt);
 }
+#endif
 
 /* ********** operator to open/close toolshelf region */
 
diff --git a/source/blender/editors/undo/ed_undo.c b/source/blender/editors/undo/ed_undo.c
index 18366f87b59..03dd1ad26e7 100644
--- a/source/blender/editors/undo/ed_undo.c
+++ b/source/blender/editors/undo/ed_undo.c
@@ -304,12 +304,44 @@ void ED_OT_undo_redo(wmOperatorType *ot)
 
 /** \} */
 
+#ifdef WITH_REDO_REGION_REMOVAL
+struct OperatorRepeatContextHandle {
+	ScrArea *restore_area;
+	ARegion *restore_region;
+};
+
+/**
+ * Resets the context to the state \a op was executed in (or at least, was in when registering).
+ * #ED_operator_repeat_reset_context should be called when done repeating!
+ */
+const OperatorRepeatContextHandle *ED_operator_repeat_prepare_context(bContext *C, wmOperator *op)
+{
+	static OperatorRepeatContextHandle context_info;
+
+	context_info.restore_area = CTX_wm_area(C);
+	context_info.restore_region = CTX_wm_region(C);
+
+	CTX_wm_area_set(C, op->execution_area);
+	CTX_wm_region_set(C, op->execution_region);
+
+	return &context_info;
+}
+/**
+ * Resets context to the old state from before #ED_operator_repeat_prepare_context was called.
+ */
+void ED_operator_repeat_reset_context(bContext *C, const OperatorRepeatContextHandle *context_info)
+{
+	CTX_wm_area_set(C, context_info->restore_area);
+	CTX_wm_region_set(C, context_info->restore_region);
+}
+#endif
+
 /* -------------------------------------------------------------------- */
 /** \name Operator Repeat
  * \{ */
 
 /* ui callbacks should call this rather than calling WM_operator_repeat() themselves */
-int ED_undo_operator_repeat(bContext *C, struct wmOperator *op)
+int ED_undo_operator_repeat(bContext *C, wmOperator *op)
 {
 	int ret = 0;
 
@@ -318,12 +350,17 @@ int ED_undo_operator_repeat(bContext *C, struct wmOperator *op)
 		wmWindowManager *wm = CTX_wm_manager(C);
 		struct Scene *scene = CTX_data_scene(C);
 
+#ifdef WITH_REDO_REGION_REMOVAL
+		const OperatorRepeatContextHandle *context_info;
+		context_info = ED_operator_repeat_prepare_context(C, op);
+#else
 		/* keep in sync with logic in view3d_panel_operator_redo() */
 		ARegion *ar = CTX_wm_region(C);
 		ARegion *ar1 = BKE_area_find_region_active_win(CTX_wm_area(C));
 
 		if (ar1)
 			CTX_wm_region_set(C, ar1);
+#endif
 
 		if ((WM_operator_repeat_check(C, op)) &&
 		    (WM_operator_poll(C, op->type)) &&
@@ -369,8 +406,12 @@ int ED_undo_operator_repeat(bContext *C, struct wmOperator *op)
 			}
 		}
 
+#ifdef WITH_REDO_REGION_REMOVAL
+		ED_operator_repeat_reset_context(C, context_info);
+#else
 		/* set region back */
 		CTX_wm_region_set(C, ar);
+#endif
 	}
 	else {
 		CLOG_WARN(&LOG, "called with NULL 'op'");
diff --git a/source/blender/makesdna/DNA_screen_types.h b/source/blender/makesdna/DNA_screen_types.h
index 46eb0cbade3..6d4494ca2d2 100644
--- a/source/blender/makesdna/DNA_screen_types.h
+++ b/source/blender/makesdna/DNA_screen_types.h
@@ -48,12 +48,19 @@ struct wmTimer;
 struct wmTooltipState;
 
 
+/* TODO Doing this is quite ugly :)
+ * Once the top-bar is merged bScreen should be refactored to use ScrAreaMap. */
+#define AREAMAP_FROM_SCREEN(screen) ((ScrAreaMap *)&(screen)->vertbase)
+
 typedef struct bScreen {
 	ID id;
-	
+
+	/* TODO Should become ScrAreaMap now.
+	 * ** NOTE: KEEP ORDER IN SYNC WITH ScrAreaMap! (see AREAMAP_FROM_SCREEN macro above) ** */
 	ListBase vertbase;					/* screens have vertices/edges to define areas */
 	ListBase edgebase;
 	ListBase areabase;
+
 	ListBase regionbase;				/* screen level regions (menus), runtime only */
 
 	struct Scene *scene DNA_DEPRECATED;
@@ -98,6 +105,14 @@ typedef struct ScrEdge {
 	int pad;
 } ScrEdge;
 
+typedef struct ScrAreaMap {
+	/* ** NOTE: KEEP ORDER IN SYNC WITH LISTBASES IN bScreen! ** */
+
+	ListBase vertbase;  /* ScrVert - screens have vertices/edges to define areas */
+	ListBase edgebase;  /* ScrEdge */
+	ListBase areabase;  /* ScrArea */
+} ScrAreaMap;
+
 typedef struct Panel {		/* the part from uiBlock that needs saved in file */
 	struct Panel *next, *prev;
 
@@ -211,6 +226,23 @@ typedef struct uiPreview {           /* some preview UI data need to be saved in
 	short pad1[3];
 } uiPreview;
 
+/* These two lines with # tell makesdna this struct can be excluded.
+ * Should be: #ifndef WITH_TOPBAR_WRITING */
+#
+#
+typedef struct ScrGlobalAreaData {
+	/* Global areas have a non-dynamic size. That means, changing the window
+	 * size doesn't affect their size at all. However, they can still be
+	 * 'collapsed', by changing this value. Ignores DPI (ED_area_global_size_y
+	 * and winx/winy don't) */
+	short cur_fixed_height;
+	/* For global areas, this is the min and max size they can use depending on
+	 * if they are 'collapsed' or not. Value is set on area creation and not
+	 * touched afterwards. */
+	short size_min, size_max;
+	short pad;
+} ScrGlobalAreaData;
+
 typedef struct ScrArea {
 	struct ScrArea *next, *prev;
 	
@@ -221,7 +253,7 @@ typedef struct ScrArea {
 
 	char spacetype, butspacetype;	/* SPACE_..., butspacetype is button arg  */
 	short winx, winy;				/* size */
-	
+
 	short headertype;				/* OLD! 0=no header, 1= down, 2= up */
 	short do_refresh;				/* private, for spacetype refresh callback */
 	short flag;
@@ -231,6 +263,9 @@ typedef struct ScrArea {
 	
 	struct SpaceType *type;		/* callbacks for this space type */
 
+	/* Non-NULL if this area is global. */
+	ScrGlobalAreaData *global;
+
 	/* A list of space links (editors) that were open in this area before. When
 	 * changing the editor type, we try to reuse old editor data from this list.
 	 * The first item is the active/visible one.
@@ -295,7 +330,11 @@ enum {
 	HEADER_NO_PULLDOWN           = (1 << 0),
 //	AREA_FLAG_DEPRECATED_1       = (1 << 1),
 //	AREA_FLAG_DEPRECATED_2       = (1 << 2),
-	AREA_TEMP_INFO               = (1 << 3),
+#ifdef DNA_DEPRECATED_ALLOW
+	AREA_TEMP_INFO               = (1 << 3), /* versioned to make slot reusable */
+#endif
+	/* update size of regions within the area */
+	AREA_FLAG_REGION_SIZE_UPDATE = (1 << 3),
 //	AREA_FLAG_DEPRECATED_4       = (1 << 4),
 //	AREA_FLAG_DEPRECATED_5       = (1 << 5),
 	/* used to check if we should switch back to prevspace (of a different type) */
@@ -413,8 +452,19 @@ enum {
 #define RGN_SPLIT_PREV		32
 
 /* region flag */
-#define RGN_FLAG_HIDDEN		1
-#define RGN_FLAG_TOO_SMALL	2
+enum {
+	RGN_FLAG_HIDDEN             = (1 << 0),
+	RGN_FLAG_TOO_SMALL          = (1 << 1),
+	/* Force delayed reinit of region size data, so that region size is calculated
+	 * just big enough to show all its content (if enough space is available).
+	 * Note that only ED_region_header supports this right now. */
+	RGN_FLAG_DYNAMIC_SIZE     = (1 << 2),
+	/* The region width stored in ARegion.sizex already has the DPI
+	 * factor applied, skip applying it again (in region_rect_recursive).
+	 * XXX Not nice at all. Leaving for now as temporary solution, but
+	 * it might cause issues if we change how ARegion.sizex is used... */
+	RGN_SIZEX_DPI_APPLIED       = (1 << 3),
+};
 
 /* region do_draw */
 #define RGN_DRAW			1
diff --git a/source/blender/makesdna/DNA_space_types.h b/source/blender/makesdna/DNA_space_types.h
index 904ffc959d8..a532dff190c 100644
--- a/source/blender/makesdna/DNA_space_types.h
+++ b/source/blender/makesdna/DNA_space_types.h
@@ -67,6 +67,14 @@ struct MovieClipScopes;
 struct Mask;
 struct BLI_mempool;
 
+/* TODO 2.8: Remove the operator redo panel/region from the 3D View and Clip
+ * Editor toolshelf. Leaving this ifdef'ed out for until new tool system and
+ * topbar design is more clear. */
+//#define WITH_REDO_REGION_REMOVAL
+/* TODO 2.8: We don't write the topbar to files currently. Uncomment this
+ * define to enable writing (should become the default in a bit). */
+//#define WITH_TOPBAR_WRITING
+
 
 /* SpaceLink (Base) ==================================== */
 
@@ -1330,6 +1338,7 @@ typedef struct SpaceClip {
 	MaskSpaceInfo mask_info;
 } SpaceClip;
 
+
 /* SpaceClip->flag */
 typedef enum eSpaceClip_Flag {
 	SC_SHOW_MARKER_PATTERN      = (1 << 0),
@@ -1378,6 +1387,22 @@ typedef enum eSpaceClip_GPencil_Source {
 	SC_GPENCIL_SRC_TRACK = 1,
 } eSpaceClip_GPencil_Source;
 
+
+/* Top Bar ======================================= */
+
+/* These two lines with # tell makesdna this struct can be excluded.
+ * Should be: #ifndef WITH_TOPBAR_WRITING */
+#
+#
+typedef struct SpaceTopBar {
+	SpaceLink *next, *prev;
+	ListBase regionbase;        /* storage of regions for inactive spaces */
+	int spacetype;
+
+	int pad;
+} SpaceTopBar;
+
+
 /* **************** SPACE DEFINES ********************* */
 
 /* space types, moved from DNA_screen_types.h */
@@ -1407,8 +1432,9 @@ typedef enum eSpace_Type {
 	SPACE_CONSOLE  = 18,
 	SPACE_USERPREF = 19,
 	SPACE_CLIP     = 20,
-	
-	SPACEICONMAX = SPACE_CLIP
+	SPACE_TOPBAR   = 21,
+
+	SPACEICONMAX = SPACE_TOPBAR
 } eSpace_Type;
 
 /* use for function args */
diff --git a/source/blender/makesdna/DNA_userdef_types.h b/source/blender/makesdna/DNA_userdef_types.h
index 1eb17b49cfd..fc10de67d48 100644
--- a/source/blender/makesdna/DNA_userdef_types.h
+++ b/source/blender/makesdna/DNA_userdef_types.h
@@ -400,7 +400,8 @@ typedef struct bTheme {
 	ThemeSpace tuserpref;
 	ThemeSpace tconsole;
 	ThemeSpace tclip;
-	
+	ThemeSpace ttopbar;
+
 	/* 20 sets of bone colors for this theme */
 	ThemeWireColor tarm[20];
 	/*ThemeWireColor tobj[20];*/
diff --git a/source/blender/makesdna/DNA_view3d_types.h b/source/blender/makesdna/DNA_view3d_types.h
index f6bd0139fdb..d7f9e33d6be 100644
--- a/source/blender/makesdna/DNA_view3d_types.h
+++ b/source/blender/makesdna/DNA_view3d_types.h
@@ -213,7 +213,7 @@ typedef struct View3D {
 	char twtype, _pad5, twflag;
 	
 	short flag3;
-	
+
 	/* afterdraw, for xray & transparent */
 	struct ListBase afterdraw_transp;
 	struct ListBase afterdraw_xray;
diff --git a/source/blender/makesdna/DNA_windowmanager_types.h b/source/blender/makesdna/DNA_windowmanager_types.h
index f03ff4ba8b7..8797f4b1fd6 100644
--- a/source/blender/makesdna/DNA_windowmanager_types.h
+++ b/source/blender/makesdna/DNA_windowmanager_types.h
@@ -32,6 +32,7 @@
 #define __DNA_WINDOWMANAGER_TYPES_H__
 
 #include "DNA_listBase.h"
+#include "DNA_screen_types.h"
 #include "DNA_vec_types.h"
 #include "DNA_userdef_types.h"
 
@@ -190,6 +191,10 @@ typedef struct wmWindow {
 
 	struct WorkSpaceInstanceHook *workspace_hook;
 
+	/** Global areas aren't part of the screen, but part of the window directly.
+	 * \note Code assumes global areas with fixed height, fixed width not supported yet */
+	ScrAreaMap global_areas;
+
 	struct bScreen *screen DNA_DEPRECATED;
 
 	short posx, posy, sizex, sizey;  /* window coords */
@@ -376,6 +381,10 @@ typedef struct wmOperator {
 	struct uiLayout *layout;      /* runtime for drawing */
 	short flag, pad[3];
 
+	/* Screen context the operator was finished in. It gets temporarily
+	 * restored during operator repeat. Only set for registered operators. */
+	struct ScrArea *execution_area;
+	struct ARegion *execution_region;
 } wmOperator;
 
 /* operator type return flags: exec(), invoke() modal(), return values */
diff --git a/source/blender/makesrna/intern/rna_screen.c b/source/blender/makesrna/intern/rna_screen.c
index 97b89937081..61ec6339ce8 100644
--- a/source/blender/makesrna/intern/rna_screen.c
+++ b/source/blender/makesrna/intern/rna_screen.c
@@ -83,6 +83,12 @@ static int rna_Screen_is_animation_playing_get(PointerRNA *UNUSED(ptr))
 	return wm ? (ED_screen_animation_playing(wm) != NULL) : 0;
 }
 
+static int rna_region_alignment_get(PointerRNA *ptr)
+{
+	ARegion *region = ptr->data;
+	return (region->alignment & ~RGN_SPLIT_PREV);
+}
+
 static void rna_Screen_layout_name_get(PointerRNA *ptr, char *value)
 {
 	const bScreen *screen = ptr->data;
@@ -130,10 +136,22 @@ static int rna_Screen_fullscreen_get(PointerRNA *ptr)
 /* UI compatible list: should not be needed, but for now we need to keep EMPTY
  * at least in the static version of this enum for python scripts. */
 static const EnumPropertyItem *rna_Area_type_itemf(bContext *UNUSED(C), PointerRNA *UNUSED(ptr),
-                                             PropertyRNA *UNUSED(prop), bool *UNUSED(r_free))
+                                             PropertyRNA *UNUSED(prop), bool *r_free)
 {
+	EnumPropertyItem *item = NULL;
+	int totitem = 0;
+
 	/* +1 to skip SPACE_EMPTY */
-	return rna_enum_space_type_items + 1;
+	for (const EnumPropertyItem *item_from = rna_enum_space_type_items + 1; item_from->identifier; item_from++) {
+		if (ELEM(item_from->value, SPACE_TOPBAR)) {
+			continue;
+		}
+		RNA_enum_item_add(&item, &totitem, item_from);
+	}
+	RNA_enum_item_end(&item, &totitem);
+	*r_free = true;
+
+	return item;
 }
 
 static int rna_Area_type_get(PointerRNA *ptr)
@@ -145,6 +163,13 @@ static int rna_Area_type_get(PointerRNA *ptr)
 
 static void rna_Area_type_set(PointerRNA *ptr, int value)
 {
+	if (ELEM(value, SPACE_TOPBAR)) {
+		/* Special case: An area can not be set to show the top-bar editor (or
+		 * other global areas). However it should still be possible to identify
+		 * its type from Python. */
+		return;
+	}
+
 	ScrArea *sa = (ScrArea *)ptr->data;
 	sa->butspacetype = value;
 }
@@ -329,6 +354,19 @@ static void rna_def_region(BlenderRNA *brna)
 	StructRNA *srna;
 	PropertyRNA *prop;
 
+	static const EnumPropertyItem alignment_types[] = {
+		{RGN_ALIGN_NONE, "NONE", 0, "None", "Don't use any fixed alignment, fill available space"},
+		{RGN_ALIGN_TOP, "TOP", 0, "Top", ""},
+		{RGN_ALIGN_BOTTOM, "BOTTOM", 0, "Bottom", ""},
+		{RGN_ALIGN_LEFT, "LEFT", 0, "Left", ""},
+		{RGN_ALIGN_RIGHT, "RIGHT", 0, "Right", ""},
+		{RGN_ALIGN_HSPLIT, "HORIZONTAL_SPLIT", 0, "Horizontal Split", ""},
+		{RGN_ALIGN_VSPLIT, "VERTICAL_SPLIT", 0, "Vertical Split", ""},
+		{RGN_ALIGN_FLOAT, "FLOAT", 0, "Float", "Region floats on screen, doesn't use any fixed alignment"},
+		{RGN_ALIGN_QSPLIT, "QUAD_SPLIT", 0, "Quad Split", "Region is split horizontally and vertically"},
+		{0, NULL, 0, NULL, NULL}
+	};
+
 	srna = RNA_def_struct(brna, "Region", NULL);
 	RNA_def_struct_ui_text(srna, "Region", "Region in a subdivided screen area");
 	RNA_def_struct_sdna(srna, "ARegion");
@@ -365,6 +403,12 @@ static void rna_def_region(BlenderRNA *brna)
 	RNA_def_property_flag(prop, PROP_NEVER_NULL);
 	RNA_def_property_ui_text(prop, "View2D", "2D view of the region");
 
+	prop = RNA_def_property(srna, "alignment", PROP_ENUM, PROP_NONE);
+	RNA_def_property_clear_flag(prop, PROP_EDITABLE);
+	RNA_def_property_enum_items(prop, alignment_types);
+	RNA_def_property_enum_funcs(prop, "rna_region_alignment_get", NULL, NULL);
+	RNA_def_property_ui_text(prop, "Alignment", "Alignment of the region within the area");
+
 	RNA_def_function(srna, "tag_redraw", "ED_region_tag_redraw");
 }
 
diff --git a/source/blender/makesrna/intern/rna_space.c b/source/blender/makesrna/intern/rna_space.c
index 35e5cde17ef..92352a27e22 100644
--- a/source/blender/makesrna/intern/rna_space.c
+++ b/source/blender/makesrna/intern/rna_space.c
@@ -87,6 +87,8 @@ const EnumPropertyItem rna_enum_space_type_items[] = {
 	                "advanced editing and script development"},
 	{SPACE_INFO, "INFO", ICON_INFO, "Info", "Main menu bar and list of error messages "
 	             "(drag down to expand and display)"},
+	/* Special case: Top-bar isn't supposed to be a regular editor for the user. */
+	{SPACE_TOPBAR, "TOPBAR", ICON_NONE, "Top Bar", "Global bar at the top of the screen for global per-window settings"},
 
 	/* Data */
 	{0, "", ICON_NONE, "Data", ""},
@@ -1806,6 +1808,7 @@ static void rna_def_space(BlenderRNA *brna)
 	prop = RNA_def_property(srna, "type", PROP_ENUM, PROP_NONE);
 	RNA_def_property_enum_sdna(prop, NULL, "spacetype");
 	RNA_def_property_enum_items(prop, rna_enum_space_type_items);
+	/* When making this editable, take care for the special case of global areas (see rna_Area_type_set). */
 	RNA_def_property_clear_flag(prop, PROP_EDITABLE);
 	RNA_def_property_ui_text(prop, "Type", "Space data type");
 
diff --git a/source/blender/makesrna/intern/rna_ui.c b/source/blender/makesrna/intern/rna_ui.c
index 40657b3a225..bb4f6719fbc 100644
--- a/source/blender/makesrna/intern/rna_ui.c
+++ b/source/blender/makesrna/intern/rna_ui.c
@@ -568,7 +568,7 @@ static void rna_Header_unregister(Main *UNUSED(bmain), StructRNA *type)
 
 	if (!ht)
 		return;
-	if (!(art = region_type_find(NULL, ht->space_type, RGN_TYPE_HEADER)))
+	if (!(art = region_type_find(NULL, ht->space_type, ht->region_type)))
 		return;
 	
 	RNA_struct_free_extension(type, &ht->ext);
@@ -592,6 +592,7 @@ static StructRNA *rna_Header_register(
 
 	/* setup dummy header & header type to store static properties in */
 	dummyheader.type = &dummyht;
+	dummyht.region_type = RGN_TYPE_HEADER; /* RGN_TYPE_HEADER by default, may be overridden */
 	RNA_pointer_create(NULL, &RNA_Header, &dummyheader, &dummyhtr);
 
 	/* validate the python class */
@@ -604,7 +605,7 @@ static StructRNA *rna_Header_register(
 		return NULL;
 	}
 
-	if (!(art = region_type_find(reports, dummyht.space_type, RGN_TYPE_HEADER)))
+	if (!(art = region_type_find(reports, dummyht.space_type, dummyht.region_type)))
 		return NULL;
 
 	/* check if we have registered this header type before, and remove it */
@@ -1240,6 +1241,14 @@ static void rna_def_header(BlenderRNA *brna)
 	RNA_def_property_flag(prop, PROP_REGISTER);
 	RNA_def_property_ui_text(prop, "Space type", "The space where the header is going to be used in");
 
+	prop = RNA_def_property(srna, "bl_region_type", PROP_ENUM, PROP_NONE);
+	RNA_def_property_enum_sdna(prop, NULL, "type->region_type");
+	RNA_def_property_enum_default(prop, RGN_TYPE_HEADER);
+	RNA_def_property_enum_items(prop, rna_enum_region_type_items);
+	RNA_def_property_flag(prop, PROP_REGISTER_OPTIONAL);
+	RNA_def_property_ui_text(prop, "Region Type", "The region where the header is going to be used in "
+	                         "(defaults to header region)");
+
 	RNA_define_verify_sdna(1);
 }
 
diff --git a/source/blender/makesrna/intern/rna_ui_api.c b/source/blender/makesrna/intern/rna_ui_api.c
index 5fc263ae171..367efd71519 100644
--- a/source/blender/makesrna/intern/rna_ui_api.c
+++ b/source/blender/makesrna/intern/rna_ui_api.c
@@ -715,6 +715,15 @@ void RNA_api_ui_layout(StructRNA *srna)
 	RNA_def_parameter_flags(parm, 0, PARM_REQUIRED);
 	api_ui_item_common_text(func);
 
+	func = RNA_def_function(srna, "template_ID_tabs", "uiTemplateIDTabs");
+	RNA_def_function_flag(func, FUNC_USE_CONTEXT);
+	api_ui_item_rna_common(func);
+	RNA_def_string(func, "new", NULL, 0, "", "Operator identifier to create a new ID block");
+	RNA_def_string(func, "open", NULL, 0, "", "Operator identifier to open a file for creating a new ID block");
+	RNA_def_string(func, "unlink", NULL, 0, "", "Operator identifier to unlink the ID block");
+	RNA_def_enum(func, "filter", id_template_filter_items, UI_TEMPLATE_ID_FILTER_ALL,
+	             "", "Optionally limit the items which can be selected");
+
 	func = RNA_def_function(srna, "template_search", "uiTemplateSearch");
 	RNA_def_function_flag(func, FUNC_USE_CONTEXT);
 	api_ui_item_rna_common(func);
@@ -756,6 +765,12 @@ void RNA_api_ui_layout(StructRNA *srna)
 	parm = RNA_def_pointer(func, "layout", "UILayout", "", "Sub-layout to put items in");
 	RNA_def_function_return(func, parm);
 
+#ifdef WITH_REDO_REGION_REMOVAL
+	func = RNA_def_function(srna, "template_operator_redo_props", "uiTemplateOperatorRedoProperties");
+	RNA_def_function_flag(func, FUNC_USE_CONTEXT);
+	RNA_def_function_ui_description(func, "Adds properties of the last executed operator using redo");
+#endif
+
 	func = RNA_def_function(srna, "template_constraint", "uiTemplateConstraint");
 	RNA_def_function_ui_description(func, "Generates the UI layout for constraints");
 	parm = RNA_def_pointer(func, "data", "Constraint", "", "Constraint data");
diff --git a/source/blender/makesrna/intern/rna_userdef.c b/source/blender/makesrna/intern/rna_userdef.c
index 2645dc081c8..8ef40f0dc66 100644
--- a/source/blender/makesrna/intern/rna_userdef.c
+++ b/source/blender/makesrna/intern/rna_userdef.c
@@ -1030,6 +1030,11 @@ static void rna_def_userdef_theme_ui(BlenderRNA *brna)
 	RNA_def_property_ui_text(prop, "State Colors", "");
 	RNA_def_property_update(prop, 0, "rna_userdef_update");
 
+	prop = RNA_def_property(srna, "wcol_tab", PROP_POINTER, PROP_NONE);
+	RNA_def_property_flag(prop, PROP_NEVER_NULL);
+	RNA_def_property_ui_text(prop, "Tab Colors", "");
+	RNA_def_property_update(prop, 0, "rna_userdef_update");
+
 	prop = RNA_def_property(srna, "menu_shadow_fac", PROP_FLOAT, PROP_FACTOR);
 	RNA_def_property_ui_text(prop, "Menu Shadow Strength", "Blending factor for menu shadows");
 	RNA_def_property_range(prop, 0.01f, 1.0f);
@@ -2960,6 +2965,20 @@ static void rna_def_userdef_theme_space_clip(BlenderRNA *brna)
 	rna_def_userdef_theme_spaces_curves(srna, false, false, false, true);
 }
 
+static void rna_def_userdef_theme_space_topbar(BlenderRNA *brna)
+{
+	StructRNA *srna;
+
+	/* space_topbar */
+
+	srna = RNA_def_struct(brna, "ThemeTopBar", NULL);
+	RNA_def_struct_sdna(srna, "ThemeSpace");
+	RNA_def_struct_clear_flag(srna, STRUCT_UNDO);
+	RNA_def_struct_ui_text(srna, "Theme Top Bar", "Theme settings for the Top Bar");
+
+	rna_def_userdef_theme_spaces_main(srna);
+}
+
 static void rna_def_userdef_themes(BlenderRNA *brna)
 {
 	StructRNA *srna;
@@ -2985,6 +3004,7 @@ static void rna_def_userdef_themes(BlenderRNA *brna)
 		{16, "FILE_BROWSER", ICON_FILESEL, "File Browser", ""},
 		{17, "CONSOLE", ICON_CONSOLE, "Python Console", ""},
 		{20, "CLIP_EDITOR", ICON_CLIP, "Movie Clip Editor", ""},
+		{21, "TOPBAR", ICON_NONE, "Top Bar", ""},
 		{0, NULL, 0, NULL, NULL}
 	};
 
@@ -3112,6 +3132,12 @@ static void rna_def_userdef_themes(BlenderRNA *brna)
 	RNA_def_property_pointer_sdna(prop, NULL, "tclip");
 	RNA_def_property_struct_type(prop, "ThemeClipEditor");
 	RNA_def_property_ui_text(prop, "Clip Editor", "");
+
+	prop = RNA_def_property(srna, "topbar", PROP_POINTER, PROP_NONE);
+	RNA_def_property_flag(prop, PROP_NEVER_NULL);
+	RNA_def_property_pointer_sdna(prop, NULL, "ttopbar");
+	RNA_def_property_struct_type(prop, "ThemeTopBar");
+	RNA_def_property_ui_text(prop, "Top Bar", "");
 }
 
 static void rna_def_userdef_addon(BlenderRNA *brna)
@@ -3202,6 +3228,7 @@ static void rna_def_userdef_dothemes(BlenderRNA *brna)
 	rna_def_userdef_theme_space_userpref(brna);
 	rna_def_userdef_theme_space_console(brna);
 	rna_def_userdef_theme_space_clip(brna);
+	rna_def_userdef_theme_space_topbar(brna);
 	rna_def_userdef_theme_colorset(brna);
 	rna_def_userdef_themes(brna);
 }
diff --git a/source/blender/windowmanager/WM_api.h b/source/blender/windowmanager/WM_api.h
index 7869973f1ec..652cdac6315 100644
--- a/source/blender/windowmanager/WM_api.h
+++ b/source/blender/windowmanager/WM_api.h
@@ -96,9 +96,11 @@ void		WM_init_splash		(struct bContext *C);
 
 void		WM_check			(struct bContext *C);
 
-int			WM_window_pixels_x		(struct wmWindow *win);
-int			WM_window_pixels_y		(struct wmWindow *win);
-bool		WM_window_is_fullscreen	(struct wmWindow *win);
+int WM_window_pixels_x(const struct wmWindow *win);
+int WM_window_pixels_y(const struct wmWindow *win);
+int WM_window_screen_pixels_x(const struct wmWindow *win);
+int WM_window_screen_pixels_y(const struct wmWindow *win);
+bool WM_window_is_fullscreen(struct wmWindow *win);
 
 void WM_windows_scene_data_sync(const ListBase *win_lb, struct Scene *scene) ATTR_NONNULL();
 struct Scene *WM_windows_scene_get_from_screen(const struct wmWindowManager *wm, const struct bScreen *screen) ATTR_NONNULL() ATTR_WARN_UNUSED_RESULT;
diff --git a/source/blender/windowmanager/WM_types.h b/source/blender/windowmanager/WM_types.h
index 4bd5bcfc056..59a3f703614 100644
--- a/source/blender/windowmanager/WM_types.h
+++ b/source/blender/windowmanager/WM_types.h
@@ -278,6 +278,7 @@ typedef struct wmNotifier {
 #define ND_LAYOUTSET		(7<<16)
 #define ND_SKETCH			(8<<16)
 #define ND_WORKSPACE_SET	(9<<16)
+#define ND_WORKSPACE_DELETE (10<<16)
 
 	/* NC_SCENE Scene */
 #define ND_SCENEBROWSE		(1<<16)
diff --git a/source/blender/windowmanager/intern/wm.c b/source/blender/windowmanager/intern/wm.c
index 27107299863..91e47b67130 100644
--- a/source/blender/windowmanager/intern/wm.c
+++ b/source/blender/windowmanager/intern/wm.c
@@ -165,6 +165,11 @@ void wm_operator_register(bContext *C, wmOperator *op)
 	wmWindowManager *wm = CTX_wm_manager(C);
 	int tot = 0;
 
+#ifdef WITH_REDO_REGION_REMOVAL
+	op->execution_area = CTX_wm_area(C);
+	op->execution_region = CTX_wm_region(C);
+#endif
+
 	BLI_addtail(&wm->operators, op);
 
 	/* only count registered operators */
@@ -465,7 +470,8 @@ void wm_add_default(Main *bmain, bContext *C)
 	WM_window_set_active_workspace(win, workspace);
 	WM_window_set_active_layout(win, workspace, layout);
 	screen->winid = win->winid;
-	
+	ED_screen_global_areas_create(win);
+
 	wm->winactive = win;
 	wm->file_saved = 1;
 	wm_window_make_drawable(wm, win);
diff --git a/source/blender/windowmanager/intern/wm_draw.c b/source/blender/windowmanager/intern/wm_draw.c
index c650bfe08c9..99319e009c8 100644
--- a/source/blender/windowmanager/intern/wm_draw.c
+++ b/source/blender/windowmanager/intern/wm_draw.c
@@ -162,6 +162,14 @@ static void wm_region_test_render_do_draw(const Scene *scene, struct Depsgraph *
 	}
 }
 
+static void wm_draw_region(bContext *C, ARegion *ar)
+{
+	CTX_wm_region_set(C, ar);
+	ED_region_do_draw(C, ar);
+	ar->do_draw = false;
+	CTX_wm_region_set(C, NULL);
+}
+
 /********************** draw all **************************/
 /* - reference method, draw all each time                 */
 
@@ -208,11 +216,10 @@ static void wm_draw_callbacks(wmWindow *win)
 static void wm_method_draw_full(bContext *C, wmWindow *win)
 {
 	bScreen *screen = WM_window_get_active_screen(win);
-	ScrArea *sa;
 	ARegion *ar;
 
 	/* draw area regions */
-	for (sa = screen->areabase.first; sa; sa = sa->next) {
+	ED_screen_areas_iter(win, screen, sa) {
 		CTX_wm_area_set(C, sa);
 
 		for (ar = sa->regionbase.first; ar; ar = ar->next) {
@@ -254,12 +261,11 @@ static void wm_method_draw_full(bContext *C, wmWindow *win)
 /*   same buffer as we swapped to the front               */
 
 /* mark area-regions to redraw if overlapped with rect */
-static void wm_flush_regions_down(bScreen *screen, rcti *dirty)
+static void wm_flush_regions_down(wmWindow *win, bScreen *screen, rcti *dirty)
 {
-	ScrArea *sa;
 	ARegion *ar;
 
-	for (sa = screen->areabase.first; sa; sa = sa->next) {
+	ED_screen_areas_iter(win, screen, sa) {
 		for (ar = sa->regionbase.first; ar; ar = ar->next) {
 			if (BLI_rcti_isect(dirty, &ar->winrct, NULL)) {
 				ar->do_draw = RGN_DRAW;
@@ -288,24 +294,25 @@ static void wm_method_draw_overlap_all(bContext *C, wmWindow *win, int exchange)
 {
 	wmWindowManager *wm = CTX_wm_manager(C);
 	bScreen *screen = WM_window_get_active_screen(win);
-	ScrArea *sa;
 	ARegion *ar;
 	static rcti rect = {0, 0, 0, 0};
 
 	/* after backbuffer selection draw, we need to redraw */
-	for (sa = screen->areabase.first; sa; sa = sa->next)
+	ED_screen_areas_iter(win, screen, sa) {
 		for (ar = sa->regionbase.first; ar; ar = ar->next)
 			if (ar->visible && !wm_area_test_invalid_backbuf(sa))
 				ED_region_tag_redraw(ar);
+	}
 
 	/* flush overlapping regions */
 	if (screen->regionbase.first) {
 		/* flush redraws of area regions up to overlapping regions */
-		for (sa = screen->areabase.first; sa; sa = sa->next)
+		ED_screen_areas_iter(win, screen, sa) {
 			for (ar = sa->regionbase.first; ar; ar = ar->next)
 				if (ar->visible && ar->do_draw)
 					wm_flush_regions_up(screen, &ar->winrct);
-		
+		}
+
 		/* flush between overlapping regions */
 		for (ar = screen->regionbase.last; ar; ar = ar->prev)
 			if (ar->visible && ar->do_draw)
@@ -314,12 +321,12 @@ static void wm_method_draw_overlap_all(bContext *C, wmWindow *win, int exchange)
 		/* flush redraws of overlapping regions down to area regions */
 		for (ar = screen->regionbase.last; ar; ar = ar->prev)
 			if (ar->visible && ar->do_draw)
-				wm_flush_regions_down(screen, &ar->winrct);
+				wm_flush_regions_down(win, screen, &ar->winrct);
 	}
 
 	/* flush drag item */
 	if (rect.xmin != rect.xmax) {
-		wm_flush_regions_down(screen, &rect);
+		wm_flush_regions_down(win, screen, &rect);
 		rect.xmin = rect.xmax = 0;
 	}
 	if (wm->drags.first) {
@@ -328,7 +335,7 @@ static void wm_method_draw_overlap_all(bContext *C, wmWindow *win, int exchange)
 	}
 	
 	/* draw marked area regions */
-	for (sa = screen->areabase.first; sa; sa = sa->next) {
+	ED_screen_areas_iter(win, screen, sa) {
 		CTX_wm_area_set(C, sa);
 
 		for (ar = sa->regionbase.first; ar; ar = ar->next) {
@@ -526,7 +533,6 @@ static void wm_method_draw_triple(bContext *C, wmWindow *win)
 	wmWindowManager *wm = CTX_wm_manager(C);
 	wmDrawData *dd, *dd_next, *drawdata = win->drawdata.first;
 	bScreen *screen = WM_window_get_active_screen(win);
-	ScrArea *sa;
 	ARegion *ar;
 	bool copytex = false;
 
@@ -567,17 +573,14 @@ static void wm_method_draw_triple(bContext *C, wmWindow *win)
 
 	wmDrawTriple *triple = drawdata->triple;
 
-	/* draw marked area regions */
-	for (sa = screen->areabase.first; sa; sa = sa->next) {
+	/* draw marked area regions (also global ones) */
+	ED_screen_areas_iter(win, screen, sa) {
 		CTX_wm_area_set(C, sa);
 
 		for (ar = sa->regionbase.first; ar; ar = ar->next) {
 			if (ar->visible && ar->do_draw) {
 				if (ar->overlap == false) {
-					CTX_wm_region_set(C, ar);
-					ED_region_do_draw(C, ar);
-					ar->do_draw = false;
-					CTX_wm_region_set(C, NULL);
+					wm_draw_region(C, ar);
 					copytex = true;
 				}
 			}
@@ -594,7 +597,7 @@ static void wm_method_draw_triple(bContext *C, wmWindow *win)
 	}
 
 	if (wm->paintcursors.first) {
-		for (sa = screen->areabase.first; sa; sa = sa->next) {
+		ED_screen_areas_iter(win, screen, sa) {
 			for (ar = sa->regionbase.first; ar; ar = ar->next) {
 				if (ar->visible && ar == screen->active_region) {
 					CTX_wm_area_set(C, sa);
@@ -614,16 +617,12 @@ static void wm_method_draw_triple(bContext *C, wmWindow *win)
 	}
 
 	/* draw overlapping area regions (always like popups) */
-	for (sa = screen->areabase.first; sa; sa = sa->next) {
+	ED_screen_areas_iter(win, screen, sa) {
 		CTX_wm_area_set(C, sa);
 
 		for (ar = sa->regionbase.first; ar; ar = ar->next) {
 			if (ar->visible && ar->overlap) {
-				CTX_wm_region_set(C, ar);
-				ED_region_do_draw(C, ar);
-				ar->do_draw = false;
-				CTX_wm_region_set(C, NULL);
-
+				wm_draw_region(C, ar);
 				wm_draw_region_blend(win, ar, triple);
 			}
 		}
@@ -662,7 +661,6 @@ static void wm_method_draw_triple_multiview(bContext *C, wmWindow *win, eStereoV
 	wmDrawData *drawdata;
 	wmDrawTriple *triple_data, *triple_all;
 	bScreen *screen = WM_window_get_active_screen(win);
-	ScrArea *sa;
 	ARegion *ar;
 	int copytex = false;
 	int id;
@@ -703,7 +701,7 @@ static void wm_method_draw_triple_multiview(bContext *C, wmWindow *win, eStereoV
 	triple_all  = ((wmDrawData *) BLI_findlink(&win->drawdata, (sview * 2) + 1))->triple;
 
 	/* draw marked area regions */
-	for (sa = screen->areabase.first; sa; sa = sa->next) {
+	ED_screen_areas_iter(win, screen, sa) {
 		CTX_wm_area_set(C, sa);
 
 		switch (sa->spacetype) {
@@ -769,7 +767,7 @@ static void wm_method_draw_triple_multiview(bContext *C, wmWindow *win, eStereoV
 	}
 
 	if (wm->paintcursors.first) {
-		for (sa = screen->areabase.first; sa; sa = sa->next) {
+		ED_screen_areas_iter(win, screen, sa) {
 			for (ar = sa->regionbase.first; ar; ar = ar->next) {
 				if (ar->visible && ar == screen->active_region) {
 					CTX_wm_area_set(C, sa);
@@ -789,7 +787,7 @@ static void wm_method_draw_triple_multiview(bContext *C, wmWindow *win, eStereoV
 	}
 
 	/* draw overlapping area regions (always like popups) */
-	for (sa = screen->areabase.first; sa; sa = sa->next) {
+	ED_screen_areas_iter(win, screen, sa) {
 		CTX_wm_area_set(C, sa);
 
 		for (ar = sa->regionbase.first; ar; ar = ar->next) {
@@ -849,7 +847,6 @@ static bool wm_draw_update_test_window(wmWindow *win)
 	/*const*/ ViewLayer *view_layer = BKE_workspace_view_layer_get(workspace, scene);
 	struct Depsgraph *depsgraph = BKE_scene_get_depsgraph(scene, view_layer, true);
 	const bScreen *screen = WM_window_get_active_screen(win);
-	ScrArea *sa;
 	ARegion *ar;
 	bool do_draw = false;
 
@@ -862,7 +859,7 @@ static bool wm_draw_update_test_window(wmWindow *win)
 			do_draw = true;
 	}
 
-	for (sa = screen->areabase.first; sa; sa = sa->next) {
+	ED_screen_areas_iter(win, screen, sa) {
 		for (ar = sa->regionbase.first; ar; ar = ar->next) {
 			wm_region_test_render_do_draw(scene, depsgraph, sa, ar);
 
@@ -963,8 +960,7 @@ void wm_draw_update(bContext *C)
 			wm_window_make_drawable(wm, win);
 
 			/* notifiers for screen redraw */
-			if (screen->do_refresh)
-				ED_screen_refresh(wm, win);
+			ED_screen_ensure_updated(wm, win, screen);
 
 			int drawmethod = wm_automatic_draw_method(win);
 
@@ -1011,17 +1007,18 @@ void wm_draw_data_free(wmWindow *win)
 void wm_draw_window_clear(wmWindow *win)
 {
 	bScreen *screen = WM_window_get_active_screen(win);
-	ScrArea *sa;
 	ARegion *ar;
 
 	wm_draw_data_free(win);
 
 	/* clear screen swap flags */
 	if (screen) {
-		for (sa = screen->areabase.first; sa; sa = sa->next)
-			for (ar = sa->regionbase.first; ar; ar = ar->next)
+		ED_screen_areas_iter(win, screen, sa) {
+			for (ar = sa->regionbase.first; ar; ar = ar->next) {
 				ar->swap = WIN_NONE_OK;
-		
+			}
+		}
+
 		screen->swap = WIN_NONE_OK;
 	}
 }
@@ -1032,7 +1029,7 @@ void wm_draw_region_clear(wmWindow *win, ARegion *ar)
 	int drawmethod = wm_automatic_draw_method(win);
 
 	if (ELEM(drawmethod, USER_DRAW_OVERLAP, USER_DRAW_OVERLAP_FLIP))
-		wm_flush_regions_down(screen, &ar->winrct);
+		wm_flush_regions_down(win, screen, &ar->winrct);
 
 	screen->do_draw = true;
 }
diff --git a/source/blender/windowmanager/intern/wm_event_system.c b/source/blender/windowmanager/intern/wm_event_system.c
index 6ec68614116..218f48e9be6 100644
--- a/source/blender/windowmanager/intern/wm_event_system.c
+++ b/source/blender/windowmanager/intern/wm_event_system.c
@@ -386,6 +386,13 @@ void wm_event_do_notifiers(bContext *C)
 						if (G.debug & G_DEBUG_EVENTS)
 							printf("%s: Workspace set %p\n", __func__, note->reference);
 					}
+					else if (note->data == ND_WORKSPACE_DELETE) {
+						WorkSpace *workspace = note->reference;
+
+						ED_workspace_delete(workspace, CTX_data_main(C), C, wm);   // XXX hrms, think this over!
+						if (G.debug & G_DEBUG_EVENTS)
+							printf("%s: Workspace delete %p\n", __func__, workspace);
+					}
 					else if (note->data == ND_LAYOUTBROWSE) {
 						bScreen *ref_screen = BKE_workspace_layout_screen_get(note->reference);
 
@@ -455,7 +462,6 @@ void wm_event_do_notifiers(bContext *C)
 				/* pass */
 			}
 			else {
-				ScrArea *sa;
 				ARegion *ar;
 
 				/* XXX context in notifiers? */
@@ -467,8 +473,8 @@ void wm_event_do_notifiers(bContext *C)
 				for (ar = screen->regionbase.first; ar; ar = ar->next) {
 					ED_region_do_listen(screen, NULL, ar, note, scene);
 				}
-				
-				for (sa = screen->areabase.first; sa; sa = sa->next) {
+
+				ED_screen_areas_iter(win, screen, sa) {
 					ED_area_do_listen(screen, sa, note, scene, workspace);
 					for (ar = sa->regionbase.first; ar; ar = ar->next) {
 						ED_region_do_listen(screen, sa, ar, note, scene);
@@ -938,7 +944,18 @@ int WM_operator_call_notest(bContext *C, wmOperator *op)
  */
 int WM_operator_repeat(bContext *C, wmOperator *op)
 {
+#ifdef WITH_REDO_REGION_REMOVAL
+	const OperatorRepeatContextHandle *context_info;
+	int retval;
+
+	context_info = ED_operator_repeat_prepare_context(C, op);
+	retval = wm_operator_exec(C, op, true, true);
+	ED_operator_repeat_reset_context(C, context_info);
+
+	return retval;
+#else
 	return wm_operator_exec(C, op, true, true);
+#endif
 }
 /**
  * \return true if #WM_operator_repeat can run
@@ -1528,17 +1545,22 @@ void wm_event_free_handler(wmEventHandler *handler)
 /* only set context when area/region is part of screen */
 static void wm_handler_op_context(bContext *C, wmEventHandler *handler, const wmEvent *event)
 {
+	wmWindow *win = CTX_wm_window(C);
 	bScreen *screen = CTX_wm_screen(C);
 	
 	if (screen && handler->op) {
 		if (handler->op_area == NULL)
 			CTX_wm_area_set(C, NULL);
 		else {
-			ScrArea *sa;
-			
-			for (sa = screen->areabase.first; sa; sa = sa->next)
-				if (sa == handler->op_area)
+			ScrArea *sa = NULL;
+
+			ED_screen_areas_iter(win, screen, sa_iter) {
+				if (sa_iter == handler->op_area) {
+					sa = sa_iter;
 					break;
+				}
+			}
+
 			if (sa == NULL) {
 				/* when changing screen layouts with running modal handlers (like render display), this
 				 * is not an error to print */
@@ -2493,13 +2515,15 @@ static int wm_event_inside_i(wmEvent *event, rcti *rect)
 
 static ScrArea *area_event_inside(bContext *C, const int xy[2])
 {
+	wmWindow *win = CTX_wm_window(C);
 	bScreen *screen = CTX_wm_screen(C);
-	ScrArea *sa;
 	
-	if (screen)
-		for (sa = screen->areabase.first; sa; sa = sa->next)
+	if (screen) {
+		ED_screen_areas_iter(win, screen, sa) {
 			if (BLI_rcti_isect_pt_v(&sa->totrct, xy))
 				return sa;
+		}
+	}
 	return NULL;
 }
 
@@ -2739,7 +2763,6 @@ void wm_event_do_handlers(bContext *C)
 			wm_tweakevent_test(C, event, action);
 
 			if ((action & WM_HANDLER_BREAK) == 0) {
-				ScrArea *sa;
 				ARegion *ar;
 	
 				/* Note: setting subwin active should be done here, after modal handlers have been done */
@@ -2755,7 +2778,7 @@ void wm_event_do_handlers(bContext *C)
 				}
 #endif
 
-				for (sa = screen->areabase.first; sa; sa = sa->next) {
+				ED_screen_areas_iter(win, screen, sa) {
 					/* after restoring a screen from SCREENMAXIMIZED we have to wait
 					 * with the screen handling till the region coordinates are updated */
 					if (screen->skip_handling == true) {
@@ -2935,24 +2958,26 @@ void WM_event_add_fileselect(bContext *C, wmOperator *op)
 		
 		if (handler->type == WM_HANDLER_FILESELECT) {
 			bScreen *screen = CTX_wm_screen(C);
-			ScrArea *sa;
+			bool cancel_handler = true;
 
 			/* find the area with the file selector for this handler */
-			for (sa = screen->areabase.first; sa; sa = sa->next) {
+			ED_screen_areas_iter(win, screen, sa) {
 				if (sa->spacetype == SPACE_FILE) {
 					SpaceFile *sfile = sa->spacedata.first;
 
 					if (sfile->op == handler->op) {
 						CTX_wm_area_set(C, sa);
 						wm_handler_fileselect_do(C, &win->modalhandlers, handler, EVT_FILESELECT_CANCEL);
+						cancel_handler = false;
 						break;
 					}
 				}
 			}
 
 			/* if not found we stop the handler without changing the screen */
-			if (!sa)
+			if (cancel_handler) {
 				wm_handler_fileselect_do(C, &win->modalhandlers, handler, EVT_FILESELECT_EXTERNAL_CANCEL);
+			}
 		}
 	}
 	
diff --git a/source/blender/windowmanager/intern/wm_operators.c b/source/blender/windowmanager/intern/wm_operators.c
index b6f7603c99f..4c96afff9a1 100644
--- a/source/blender/windowmanager/intern/wm_operators.c
+++ b/source/blender/windowmanager/intern/wm_operators.c
@@ -1498,13 +1498,15 @@ static uiBlock *wm_block_create_redo(bContext *C, ARegion *ar, void *arg_op)
 
 	if (op->type->flag & OPTYPE_MACRO) {
 		for (op = op->macro.first; op; op = op->next) {
-			uiTemplateOperatorPropertyButs(C, layout, op, NULL, 'H', UI_TEMPLATE_OP_PROPS_SHOW_TITLE);
+			uiTemplateOperatorPropertyButs(C, layout, op, NULL, UI_BUT_LABEL_ALIGN_SPLIT_COLUMN,
+			                               UI_TEMPLATE_OP_PROPS_SHOW_TITLE);
 			if (op->next)
 				uiItemS(layout);
 		}
 	}
 	else {
-		uiTemplateOperatorPropertyButs(C, layout, op, NULL, 'H', UI_TEMPLATE_OP_PROPS_SHOW_TITLE);
+		uiTemplateOperatorPropertyButs(C, layout, op, NULL, UI_BUT_LABEL_ALIGN_SPLIT_COLUMN,
+		                               UI_TEMPLATE_OP_PROPS_SHOW_TITLE);
 	}
 	
 	UI_block_bounds_set_popup(block, 4, 0, 0);
@@ -1573,7 +1575,8 @@ static uiBlock *wm_block_dialog_create(bContext *C, ARegion *ar, void *userData)
 
 	layout = UI_block_layout(block, UI_LAYOUT_VERTICAL, UI_LAYOUT_PANEL, 0, 0, data->width, data->height, 0, style);
 	
-	uiTemplateOperatorPropertyButs(C, layout, op, NULL, 'H', UI_TEMPLATE_OP_PROPS_SHOW_TITLE);
+	uiTemplateOperatorPropertyButs(C, layout, op, NULL, UI_BUT_LABEL_ALIGN_SPLIT_COLUMN,
+	                               UI_TEMPLATE_OP_PROPS_SHOW_TITLE);
 	
 	/* clear so the OK button is left alone */
 	UI_block_func_set(block, NULL, NULL, NULL);
@@ -1612,7 +1615,7 @@ static uiBlock *wm_operator_ui_create(bContext *C, ARegion *ar, void *userData)
 	layout = UI_block_layout(block, UI_LAYOUT_VERTICAL, UI_LAYOUT_PANEL, 0, 0, data->width, data->height, 0, style);
 
 	/* since ui is defined the auto-layout args are not used */
-	uiTemplateOperatorPropertyButs(C, layout, op, NULL, 'V', 0);
+	uiTemplateOperatorPropertyButs(C, layout, op, NULL, UI_BUT_LABEL_ALIGN_COLUMN, 0);
 
 	UI_block_func_set(block, NULL, NULL, NULL);
 
diff --git a/source/blender/windowmanager/intern/wm_window.c b/source/blender/windowmanager/intern/wm_window.c
index 9b0d8db68ce..166d97d6b5e 100644
--- a/source/blender/windowmanager/intern/wm_window.c
+++ b/source/blender/windowmanager/intern/wm_window.c
@@ -208,6 +208,8 @@ void wm_window_free(bContext *C, wmWindowManager *wm, wmWindow *win)
 			CTX_wm_window_set(C, NULL);
 	}
 
+	BKE_screen_area_map_free(&win->global_areas);
+
 	/* end running jobs, a job end also removes its timer */
 	for (wt = wm->timers.first; wt; wt = wtnext) {
 		wtnext = wt->next;
@@ -302,6 +304,7 @@ wmWindow *wm_window_copy(bContext *C, wmWindow *win_src, const bool duplicate_la
 	WM_window_set_active_workspace(win_dst, workspace);
 	layout_new = duplicate_layout ? ED_workspace_layout_duplicate(workspace, layout_old, win_dst) : layout_old;
 	WM_window_set_active_layout(win_dst, workspace, layout_new);
+	ED_screen_global_areas_create(win_dst);
 
 	win_dst->drawmethod = U.wmdrawmethod;
 
@@ -782,6 +785,11 @@ void wm_window_ghostwindows_ensure(wmWindowManager *wm)
 			WM_event_add_dropbox_handler(&win->handlers, lb);
 		}
 		wm_window_title(wm, win);
+
+		/* add topbar */
+		if (BLI_listbase_is_empty(&win->global_areas.areabase)) {
+			ED_screen_global_areas_create(win);
+		}
 	}
 }
 
@@ -1008,6 +1016,8 @@ int wm_window_new_exec(bContext *C, wmOperator *op)
 		win_dst->scene = win_src->scene;
 		screen_new->winid = win_dst->winid;
 		CTX_wm_window_set(C, win_dst);
+
+		ED_screen_global_areas_create(win_dst);
 		ED_screen_refresh(CTX_wm_manager(C), win_dst);
 	}
 
@@ -2074,19 +2084,35 @@ float WM_cursor_pressure(const struct wmWindow *win)
 
 /* support for native pixel size */
 /* mac retina opens window in size X, but it has up to 2 x more pixels */
-int WM_window_pixels_x(wmWindow *win)
+int WM_window_pixels_x(const wmWindow *win)
 {
 	float f = GHOST_GetNativePixelSize(win->ghostwin);
 	
 	return (int)(f * (float)win->sizex);
 }
-
-int WM_window_pixels_y(wmWindow *win)
+int WM_window_pixels_y(const wmWindow *win)
 {
 	float f = GHOST_GetNativePixelSize(win->ghostwin);
 	
 	return (int)(f * (float)win->sizey);
-	
+}
+
+/**
+ * Get the total pixels that are usable by the screen-layouts, excluding global areas.
+ */
+int WM_window_screen_pixels_x(const wmWindow *win)
+{
+	return WM_window_pixels_x(win);
+}
+int WM_window_screen_pixels_y(const wmWindow *win)
+{
+	short screen_size_y = WM_window_pixels_y(win);
+
+	for (ScrArea *sa = win->global_areas.areabase.first; sa; sa = sa->next) {
+		screen_size_y -= ED_area_global_size_y(sa);
+	}
+
+	return screen_size_y;
 }
 
 bool WM_window_is_fullscreen(wmWindow *win)