UI: move top-bar into the spaces header

Currently this is only in the 3D viewport however all spaces
that use the tool-system will have this region added.

D4680 by @brecht with own updates.

12 files changed, 176 insertions, 43 deletions

diff --git a/source/blender/editors/include/ED_screen.h b/source/blender/editors/include/ED_screen.h
index 04bbbbdf25f..b4349ff6cc7 100644
--- a/source/blender/editors/include/ED_screen.h
+++ b/source/blender/editors/include/ED_screen.h
@@ -131,10 +131,21 @@ bool ED_region_snap_size_apply(struct ARegion *ar, int snap_flag);
 void ED_region_do_msg_notify_tag_redraw(struct bContext *C,
                                         struct wmMsgSubscribeKey *msg_key,
                                         struct wmMsgSubscribeValue *msg_val);
+void ED_area_do_msg_notify_tag_redraw(struct bContext *C,
+                                      struct wmMsgSubscribeKey *msg_key,
+                                      struct wmMsgSubscribeValue *msg_val);
 void ED_area_do_msg_notify_tag_refresh(struct bContext *C,
                                        struct wmMsgSubscribeKey *msg_key,
                                        struct wmMsgSubscribeValue *msg_val);
 
+void ED_area_do_mgs_subscribe_for_tool_header(const struct bContext *C,
+                                              struct WorkSpace *workspace,
+                                              struct Scene *scene,
+                                              struct bScreen *screen,
+                                              struct ScrArea *sa,
+                                              struct ARegion *ar,
+                                              struct wmMsgBus *mbus);
+
 /* message bus */
 void ED_region_message_subscribe(struct bContext *C,
                                  struct WorkSpace *workspace,
diff --git a/source/blender/editors/interface/interface_context_menu.c b/source/blender/editors/interface/interface_context_menu.c
index c8800f495ce..b6d9863f9b5 100644
--- a/source/blender/editors/interface/interface_context_menu.c
+++ b/source/blender/editors/interface/interface_context_menu.c
@@ -1064,7 +1064,7 @@ bool ui_popup_context_menu_for_button(bContext *C, uiBut *but)
     if (!ar) {
       /* skip */
     }
-    else if (ar->regiontype == RGN_TYPE_HEADER) {
+    else if (ELEM(ar->regiontype, RGN_TYPE_HEADER, RGN_TYPE_TOOL_HEADER)) {
       uiItemMenuF(layout, IFACE_("Header"), ICON_NONE, ED_screens_header_tools_menu_create, NULL);
     }
     else if (ar->regiontype == RGN_TYPE_NAV_BAR) {
diff --git a/source/blender/editors/interface/interface_handlers.c b/source/blender/editors/interface/interface_handlers.c
index e9914ce6f24..72aa9920248 100644
--- a/source/blender/editors/interface/interface_handlers.c
+++ b/source/blender/editors/interface/interface_handlers.c
@@ -1778,7 +1778,11 @@ static bool ui_but_drag_init(bContext *C,
 
       /* Initialize alignment for single row/column regions,
        * otherwise we use the relative position of the first other button dragged over. */
-      if (ELEM(data->region->regiontype, RGN_TYPE_NAV_BAR, RGN_TYPE_HEADER, RGN_TYPE_FOOTER)) {
+      if (ELEM(data->region->regiontype,
+               RGN_TYPE_NAV_BAR,
+               RGN_TYPE_HEADER,
+               RGN_TYPE_TOOL_HEADER,
+               RGN_TYPE_FOOTER)) {
         int lock_axis = -1;
         if (ELEM(data->region->alignment, RGN_ALIGN_LEFT, RGN_ALIGN_RIGHT)) {
           lock_axis = 0;
diff --git a/source/blender/editors/interface/interface_region_menu_popup.c b/source/blender/editors/interface/interface_region_menu_popup.c
index d364bf7e102..b97cbcdfef5 100644
--- a/source/blender/editors/interface/interface_region_menu_popup.c
+++ b/source/blender/editors/interface/interface_region_menu_popup.c
@@ -279,7 +279,7 @@ static uiBlock *ui_block_func_POPUP(bContext *C, uiPopupBlockHandle *handle, voi
       ScrArea *sa = CTX_wm_area(C);
       ARegion *ar = CTX_wm_region(C);
       if (sa && ar) {
-        if (ar->regiontype == RGN_TYPE_HEADER) {
+        if (ELEM(ar->regiontype, RGN_TYPE_HEADER, RGN_TYPE_TOOL_HEADER)) {
           if (ED_area_header_alignment(sa) == RGN_ALIGN_BOTTOM) {
             UI_block_direction_set(block, UI_DIR_UP);
             UI_block_order_flip(block);
diff --git a/source/blender/editors/interface/interface_region_popover.c b/source/blender/editors/interface/interface_region_popover.c
index bbf3df6a264..110c8827849 100644
--- a/source/blender/editors/interface/interface_region_popover.c
+++ b/source/blender/editors/interface/interface_region_popover.c
@@ -187,7 +187,7 @@ static uiBlock *ui_block_func_POPOVER(bContext *C, uiPopupBlockHandle *handle, v
       }
       /* Prefer popover from header to be positioned into the editor. */
       else if (sa && ar) {
-        if (ar->regiontype == RGN_TYPE_HEADER) {
+        if (ELEM(ar->regiontype, RGN_TYPE_HEADER, RGN_TYPE_TOOL_HEADER)) {
           if (ED_area_header_alignment(sa) == RGN_ALIGN_BOTTOM) {
             UI_block_direction_set(block, UI_DIR_UP | UI_DIR_CENTER_X);
           }
diff --git a/source/blender/editors/interface/interface_templates.c b/source/blender/editors/interface/interface_templates.c
index 76d82b93ad1..bbff2c16636 100644
--- a/source/blender/editors/interface/interface_templates.c
+++ b/source/blender/editors/interface/interface_templates.c
@@ -127,11 +127,8 @@ static void template_add_button_search_menu(const bContext *C,
 
   if (use_previews) {
     ARegion *region = CTX_wm_region(C);
-    ScrArea *area = CTX_wm_area(C);
-    /* XXX ugly top-bar exception */
-    const bool use_big_size = (
-        /* silly check, could be more generic */
-        (region->regiontype != RGN_TYPE_HEADER) && (area->spacetype != SPACE_TOPBAR));
+    /* Ugly tool header exception. */
+    const bool use_big_size = (region->regiontype != RGN_TYPE_TOOL_HEADER);
     /* 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));
diff --git a/source/blender/editors/screen/area.c b/source/blender/editors/screen/area.c
index 1aa54bcd8b5..250a4171e8a 100644
--- a/source/blender/editors/screen/area.c
+++ b/source/blender/editors/screen/area.c
@@ -421,17 +421,18 @@ static void region_draw_status_text(ScrArea *sa, ARegion *ar)
   BLF_draw(fontid, ar->headerstr, BLF_DRAW_STR_DUMMY_MAX);
 }
 
-/* Follow wmMsgNotifyFn spec */
-void ED_region_do_msg_notify_tag_redraw(bContext *UNUSED(C),
-                                        wmMsgSubscribeKey *UNUSED(msg_key),
-                                        wmMsgSubscribeValue *msg_val)
+void ED_region_do_msg_notify_tag_redraw(
+    /* Follow wmMsgNotifyFn spec */
+    bContext *UNUSED(C),
+    wmMsgSubscribeKey *UNUSED(msg_key),
+    wmMsgSubscribeValue *msg_val)
 {
   ARegion *ar = msg_val->owner;
   ED_region_tag_redraw(ar);
 
   /* This avoids _many_ situations where header/properties control display settings.
    * the common case is space properties in the header */
-  if (ELEM(ar->regiontype, RGN_TYPE_HEADER, RGN_TYPE_UI)) {
+  if (ELEM(ar->regiontype, RGN_TYPE_HEADER, RGN_TYPE_TOOL_HEADER, RGN_TYPE_UI)) {
     while (ar && ar->prev) {
       ar = ar->prev;
     }
@@ -442,15 +443,48 @@ void ED_region_do_msg_notify_tag_redraw(bContext *UNUSED(C),
     }
   }
 }
-/* Follow wmMsgNotifyFn spec */
-void ED_area_do_msg_notify_tag_refresh(bContext *UNUSED(C),
-                                       wmMsgSubscribeKey *UNUSED(msg_key),
-                                       wmMsgSubscribeValue *msg_val)
+/**
+ * Use #ED_region_do_msg_notify_tag_redraw where possible, this draws too much typically.
+ */
+void ED_area_do_msg_notify_tag_redraw(
+    /* Follow wmMsgNotifyFn spec */
+    bContext *UNUSED(C),
+    wmMsgSubscribeKey *UNUSED(msg_key),
+    wmMsgSubscribeValue *msg_val)
+{
+  ScrArea *sa = msg_val->owner;
+  ED_area_tag_redraw(sa);
+}
+void ED_area_do_msg_notify_tag_refresh(
+    /* Follow wmMsgNotifyFn spec */
+    bContext *UNUSED(C),
+    wmMsgSubscribeKey *UNUSED(msg_key),
+    wmMsgSubscribeValue *msg_val)
 {
   ScrArea *sa = msg_val->user_data;
   ED_area_tag_refresh(sa);
 }
 
+void ED_area_do_mgs_subscribe_for_tool_header(
+    /* Follow ARegionType.message_subscribe */
+    const struct bContext *UNUSED(C),
+    struct WorkSpace *workspace,
+    struct Scene *UNUSED(scene),
+    struct bScreen *UNUSED(screen),
+    struct ScrArea *sa,
+    struct ARegion *UNUSED(ar),
+    struct wmMsgBus *mbus)
+{
+  /* TODO(campbell): investigate why ED_region_do_msg_notify_tag_redraw doesn't work here. */
+  wmMsgSubscribeValue msg_sub_value_region_tag_redraw = {
+      .owner = sa,
+      .user_data = sa,
+      .notify = ED_area_do_msg_notify_tag_redraw,
+  };
+  WM_msg_subscribe_rna_prop(
+      mbus, &workspace->id, workspace, WorkSpace, tools, &msg_sub_value_region_tag_redraw);
+}
+
 /**
  * Although there's no general support for minimizing areas, the status-bar can
  * be snapped to be only a few pixels high. A few pixels rather than 0 so it
@@ -931,7 +965,7 @@ static bool region_azone_edge_poll(const ARegion *ar, const bool is_fullscreen)
   if (is_hidden && is_fullscreen) {
     return false;
   }
-  if (!is_hidden && ar->regiontype == RGN_TYPE_HEADER) {
+  if (!is_hidden && ELEM(ar->regiontype, RGN_TYPE_HEADER, RGN_TYPE_TOOL_HEADER)) {
     return false;
   }
 
@@ -1011,6 +1045,12 @@ static void region_azones_add(const bScreen *screen, ScrArea *sa, ARegion *ar, c
 {
   const bool is_fullscreen = screen->state == SCREENFULL;
 
+  /* Only display tab or icons when the header region is hidden
+   * (not the tool header - they overlap). */
+  if (ar->regiontype == RGN_TYPE_TOOL_HEADER) {
+    return;
+  }
+
   /* edge code (t b l r) is along which area edge azone will be drawn */
   if (alignment == RGN_ALIGN_TOP)
     region_azone_edge_initialize(sa, ar, AE_BOTTOM_TO_TOPLEFT, is_fullscreen);
@@ -1183,6 +1223,9 @@ static void region_rect_recursive(
   else if (ar->regiontype == RGN_TYPE_HEADER) {
     prefsizey = ED_area_headersize();
   }
+  else if (ar->regiontype == RGN_TYPE_TOOL_HEADER) {
+    prefsizey = ED_area_headersize();
+  }
   else if (ar->regiontype == RGN_TYPE_FOOTER) {
     prefsizey = ED_area_footersize();
   }
@@ -1937,7 +1980,7 @@ void ED_area_newspace(bContext *C, ScrArea *sa, int type, const bool skip_ar_exi
       /* Spaces with footer. */
       if (st->spaceid == SPACE_TEXT) {
         for (ARegion *ar = sa->regionbase.first; ar; ar = ar->next) {
-          if (ar->regiontype == RGN_TYPE_HEADER) {
+          if (ELEM(ar->regiontype, RGN_TYPE_HEADER, RGN_TYPE_TOOL_HEADER)) {
             ar->alignment = header_alignment;
           }
           if (ar->regiontype == RGN_TYPE_FOOTER) {
@@ -1950,7 +1993,7 @@ void ED_area_newspace(bContext *C, ScrArea *sa, int type, const bool skip_ar_exi
       }
       else {
         for (ARegion *ar = sa->regionbase.first; ar; ar = ar->next) {
-          if (ar->regiontype == RGN_TYPE_HEADER) {
+          if (ELEM(ar->regiontype, RGN_TYPE_HEADER, RGN_TYPE_TOOL_HEADER)) {
             ar->alignment = header_alignment;
             break;
           }
@@ -2035,6 +2078,7 @@ static ThemeColorID region_background_color_id(const bContext *C, const ARegion
 
   switch (region->regiontype) {
     case RGN_TYPE_HEADER:
+    case RGN_TYPE_TOOL_HEADER:
       if (ED_screen_area_active(C) || ED_area_is_global(area)) {
         return TH_HEADER;
       }
diff --git a/source/blender/editors/screen/screen_edit.c b/source/blender/editors/screen/screen_edit.c
index 8caa960bb9a..259076f194f 100644
--- a/source/blender/editors/screen/screen_edit.c
+++ b/source/blender/editors/screen/screen_edit.c
@@ -428,6 +428,10 @@ static void screen_refresh_headersizes(void)
     if (art)
       art->prefsizey = ED_area_headersize();
 
+    art = BKE_regiontype_from_id(st, RGN_TYPE_TOOL_HEADER);
+    if (art)
+      art->prefsizey = ED_area_headersize();
+
     art = BKE_regiontype_from_id(st, RGN_TYPE_FOOTER);
     if (art)
       art->prefsizey = ED_area_headersize();
@@ -679,7 +683,7 @@ void ED_screen_set_active_region(bContext *C, wmWindow *win, const int xy[2])
 
         if (do_draw) {
           for (ar = area_iter->regionbase.first; ar; ar = ar->next) {
-            if (ar->regiontype == RGN_TYPE_HEADER) {
+            if (ELEM(ar->regiontype, RGN_TYPE_HEADER, RGN_TYPE_TOOL_HEADER)) {
               ED_region_tag_redraw_no_rebuild(ar);
             }
           }
@@ -813,16 +817,14 @@ static int screen_global_header_size(void)
 
 static void screen_global_topbar_area_refresh(wmWindow *win, bScreen *screen)
 {
-  const short size_min = screen_global_header_size();
-  const short size_max = 2.25 * screen_global_header_size();
-  const short size = (screen->flag & SCREEN_COLLAPSE_TOPBAR) ? size_min : size_max;
+  const short size = screen_global_header_size();
   rcti rect;
 
   BLI_rcti_init(&rect, 0, WM_window_pixels_x(win) - 1, 0, WM_window_pixels_y(win) - 1);
-  rect.ymin = rect.ymax - size_max;
+  rect.ymin = rect.ymax - size;
 
   screen_global_area_refresh(
-      win, screen, SPACE_TOPBAR, GLOBAL_AREA_ALIGN_TOP, &rect, size, size_min, size_max);
+      win, screen, SPACE_TOPBAR, GLOBAL_AREA_ALIGN_TOP, &rect, size, size, size);
 }
 
 static void screen_global_statusbar_area_refresh(wmWindow *win, bScreen *screen)
@@ -845,14 +847,11 @@ void ED_screen_global_areas_sync(wmWindow *win)
    * global areas should just become part of the screen instead. */
   bScreen *screen = BKE_workspace_active_screen_get(win->workspace_hook);
 
-  screen->flag &= ~(SCREEN_COLLAPSE_STATUSBAR | SCREEN_COLLAPSE_TOPBAR);
+  screen->flag &= ~SCREEN_COLLAPSE_STATUSBAR;
 
   for (ScrArea *area = win->global_areas.areabase.first; area; area = area->next) {
     if (area->global->cur_fixed_height == area->global->size_min) {
-      if (area->spacetype == SPACE_TOPBAR) {
-        screen->flag |= SCREEN_COLLAPSE_TOPBAR;
-      }
-      else if (area->spacetype == SPACE_STATUSBAR) {
+      if (area->spacetype == SPACE_STATUSBAR) {
         screen->flag |= SCREEN_COLLAPSE_STATUSBAR;
       }
     }
@@ -1278,6 +1277,7 @@ ScrArea *ED_screen_state_toggle(bContext *C, wmWindow *win, ScrArea *sa, const s
         if (ELEM(ar->regiontype,
                  RGN_TYPE_UI,
                  RGN_TYPE_HEADER,
+                 RGN_TYPE_TOOL_HEADER,
                  RGN_TYPE_FOOTER,
                  RGN_TYPE_TOOLS,
                  RGN_TYPE_NAV_BAR,
diff --git a/source/blender/editors/screen/screen_ops.c b/source/blender/editors/screen/screen_ops.c
index 07f60552ce4..4e39f56ddee 100644
--- a/source/blender/editors/screen/screen_ops.c
+++ b/source/blender/editors/screen/screen_ops.c
@@ -1324,7 +1324,7 @@ static void area_move_set_limits(
       int size_max = ED_area_global_max_size_y(area) - 1;
 
       size_min = max_ii(size_min, 0);
-      BLI_assert(size_min < size_max);
+      BLI_assert(size_min <= size_max);
 
       /* logic here is only tested for lower edge :) */
       /* left edge */
@@ -2338,12 +2338,12 @@ static int area_max_regionsize(ScrArea *sa, ARegion *scalear, AZEdge edge)
       }
       else if (scalear->alignment == RGN_ALIGN_TOP &&
                (ar->alignment == RGN_ALIGN_BOTTOM ||
-                ELEM(ar->regiontype, RGN_TYPE_HEADER, RGN_TYPE_FOOTER))) {
+                ELEM(ar->regiontype, RGN_TYPE_HEADER, RGN_TYPE_TOOL_HEADER, RGN_TYPE_FOOTER))) {
         dist -= ar->winy;
       }
       else if (scalear->alignment == RGN_ALIGN_BOTTOM &&
                (ar->alignment == RGN_ALIGN_TOP ||
-                ELEM(ar->regiontype, RGN_TYPE_HEADER, RGN_TYPE_FOOTER))) {
+                ELEM(ar->regiontype, RGN_TYPE_HEADER, RGN_TYPE_TOOL_HEADER, RGN_TYPE_FOOTER))) {
         dist -= ar->winy;
       }
     }
@@ -2430,6 +2430,18 @@ static void region_scale_toggle_hidden(bContext *C, RegionMoveData *rmd)
 
   region_toggle_hidden(C, rmd->ar, 0);
   region_scale_validate_size(rmd);
+
+  if ((rmd->ar->flag & RGN_FLAG_HIDDEN) == 0) {
+    if (rmd->ar->regiontype == RGN_TYPE_HEADER) {
+      ARegion *ar_tool_header = BKE_area_find_region_type(rmd->sa, RGN_TYPE_TOOL_HEADER);
+      if (ar_tool_header != NULL) {
+        if ((ar_tool_header->flag & RGN_FLAG_HIDDEN_BY_USER) == 0 &&
+            (ar_tool_header->flag & RGN_FLAG_HIDDEN) != 0) {
+          region_toggle_hidden(C, ar_tool_header, 0);
+        }
+      }
+    }
+  }
 }
 
 static int region_scale_modal(bContext *C, wmOperator *op, const wmEvent *event)
@@ -3794,11 +3806,16 @@ void ED_screens_header_tools_menu_create(bContext *C, uiLayout *layout, void *UN
   ARegion *ar = CTX_wm_region(C);
   const char *but_flip_str = (ar->alignment == RGN_ALIGN_TOP) ? IFACE_("Flip to Bottom") :
                                                                 IFACE_("Flip to Top");
-
-  if (!ELEM(sa->spacetype, SPACE_TOPBAR)) {
+  {
     PointerRNA ptr;
     RNA_pointer_create((ID *)CTX_wm_screen(C), &RNA_Space, sa->spacedata.first, &ptr);
     uiItemR(layout, &ptr, "show_region_header", 0, IFACE_("Show Header"), ICON_NONE);
+    if (BKE_area_find_region_type(sa, RGN_TYPE_TOOL_HEADER)) {
+      ARegion *ar_header = BKE_area_find_region_type(sa, RGN_TYPE_HEADER);
+      uiLayoutSetActive(layout, (ar_header->flag & RGN_FLAG_HIDDEN) == 0);
+      uiItemR(layout, &ptr, "show_region_tool_header", 0, IFACE_("Show Tool Settings"), ICON_NONE);
+      uiLayoutSetActive(layout, true);
+    }
   }
 
   /* default is WM_OP_INVOKE_REGION_WIN, which we don't want here. */
@@ -4058,7 +4075,7 @@ static int match_region_with_redraws(int spacetype,
     if (redraws & TIME_ALL_BUTS_WIN)
       return 1;
   }
-  else if (regiontype == RGN_TYPE_HEADER) {
+  else if (ELEM(regiontype, RGN_TYPE_HEADER, RGN_TYPE_TOOL_HEADER)) {
     if (spacetype == SPACE_ACTION)
       return 1;
   }
diff --git a/source/blender/editors/space_image/space_image.c b/source/blender/editors/space_image/space_image.c
index ded19b10300..1e1d1e570b3 100644
--- a/source/blender/editors/space_image/space_image.c
+++ b/source/blender/editors/space_image/space_image.c
@@ -134,6 +134,13 @@ static SpaceLink *image_new(const ScrArea *UNUSED(area), const Scene *UNUSED(sce
   scopes_new(&simage->scopes);
   simage->sample_line_hist.height = 100;
 
+  /* tool header */
+  ar = MEM_callocN(sizeof(ARegion), "tool header for image");
+
+  BLI_addtail(&simage->regionbase, ar);
+  ar->regiontype = RGN_TYPE_TOOL_HEADER;
+  ar->alignment = (U.uiflag & USER_HEADER_BOTTOM) ? RGN_ALIGN_BOTTOM : RGN_ALIGN_TOP;
+
   /* header */
   ar = MEM_callocN(sizeof(ARegion), "header for image");
 
@@ -1033,6 +1040,17 @@ void ED_spacetype_image(void)
   art->draw = image_tools_region_draw;
   BLI_addhead(&st->regiontypes, art);
 
+  /* regions: tool header */
+  art = MEM_callocN(sizeof(ARegionType), "spacetype image tool header region");
+  art->regionid = RGN_TYPE_TOOL_HEADER;
+  art->prefsizey = HEADERY;
+  art->keymapflag = ED_KEYMAP_UI | ED_KEYMAP_VIEW2D | ED_KEYMAP_FRAMES | ED_KEYMAP_HEADER;
+  art->listener = image_header_region_listener;
+  art->init = image_header_region_init;
+  art->draw = image_header_region_draw;
+  art->message_subscribe = ED_area_do_mgs_subscribe_for_tool_header;
+  BLI_addhead(&st->regiontypes, art);
+
   /* regions: header */
   art = MEM_callocN(sizeof(ARegionType), "spacetype image region");
   art->regionid = RGN_TYPE_HEADER;
diff --git a/source/blender/editors/space_topbar/space_topbar.c b/source/blender/editors/space_topbar/space_topbar.c
index 46a86bcbc86..8b290009a97 100644
--- a/source/blender/editors/space_topbar/space_topbar.c
+++ b/source/blender/editors/space_topbar/space_topbar.c
@@ -71,10 +71,6 @@ static SpaceLink *topbar_new(const ScrArea *UNUSED(area), const Scene *UNUSED(sc
   ar->alignment = RGN_ALIGN_RIGHT | RGN_SPLIT_PREV;
 
   /* main regions */
-  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), "main region of topbar");
   BLI_addtail(&stopbar->regionbase, ar);
   ar->regiontype = RGN_TYPE_WINDOW;
diff --git a/source/blender/editors/space_view3d/space_view3d.c b/source/blender/editors/space_view3d/space_view3d.c
index a829584b580..8a0d1b5b322 100644
--- a/source/blender/editors/space_view3d/space_view3d.c
+++ b/source/blender/editors/space_view3d/space_view3d.c
@@ -293,6 +293,13 @@ static SpaceLink *view3d_new(const ScrArea *UNUSED(sa), const Scene *scene)
   v3d->vertex_opacity = 1.0f;
   v3d->gp_flag |= V3D_GP_SHOW_EDIT_LINES;
 
+  /* tool header */
+  ar = MEM_callocN(sizeof(ARegion), "tool header for view3d");
+
+  BLI_addtail(&v3d->regionbase, ar);
+  ar->regiontype = RGN_TYPE_TOOL_HEADER;
+  ar->alignment = (U.uiflag & USER_HEADER_BOTTOM) ? RGN_ALIGN_BOTTOM : RGN_ALIGN_TOP;
+
   /* header */
   ar = MEM_callocN(sizeof(ARegion), "header for view3d");
 
@@ -1120,6 +1127,34 @@ static void view3d_header_region_listener(wmWindow *UNUSED(win),
       }
       break;
   }
+
+  /* From topbar, which ones are needed? split per header? */
+  /* Disable for now, re-enable if neede, or remove - campbell. */
+#if 0
+  /* 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;
+    case NC_GPENCIL:
+      if (wmn->data == ND_DATA) {
+        ED_region_tag_redraw(ar);
+      }
+      break;
+  }
+#endif
 }
 
 static void view3d_header_region_message_subscribe(const struct bContext *UNUSED(C),
@@ -1489,6 +1524,17 @@ void ED_spacetype_view3d(void)
   art->draw = view3d_tools_region_draw;
   BLI_addhead(&st->regiontypes, art);
 
+  /* regions: tool header */
+  art = MEM_callocN(sizeof(ARegionType), "spacetype view3d tool header region");
+  art->regionid = RGN_TYPE_TOOL_HEADER;
+  art->prefsizey = HEADERY;
+  art->keymapflag = ED_KEYMAP_UI | ED_KEYMAP_VIEW2D | ED_KEYMAP_FRAMES | ED_KEYMAP_HEADER;
+  art->listener = view3d_header_region_listener;
+  art->init = view3d_header_region_init;
+  art->draw = view3d_header_region_draw;
+  art->message_subscribe = view3d_header_region_message_subscribe;
+  BLI_addhead(&st->regiontypes, art);
+
   /* regions: header */
   art = MEM_callocN(sizeof(ARegionType), "spacetype view3d header region");
   art->regionid = RGN_TYPE_HEADER;
@@ -1497,7 +1543,7 @@ void ED_spacetype_view3d(void)
   art->listener = view3d_header_region_listener;
   art->init = view3d_header_region_init;
   art->draw = view3d_header_region_draw;
-  art->message_subscribe = view3d_header_region_message_subscribe;
+  art->message_subscribe = ED_area_do_mgs_subscribe_for_tool_header;
   BLI_addhead(&st->regiontypes, art);
 
   /* regions: hud */