5 files changed, 50 insertions, 12 deletions

diff --git a/source/blender/editors/include/ED_screen.h b/source/blender/editors/include/ED_screen.h
index 1b5425b54c8..a2a619209db 100644
--- a/source/blender/editors/include/ED_screen.h
+++ b/source/blender/editors/include/ED_screen.h
@@ -150,6 +150,8 @@ void    ED_area_swapspace(struct bContext *C, ScrArea *sa1, ScrArea *sa2);
 int     ED_area_headersize(void);
 int     ED_area_header_alignment(const ScrArea *area);
 int     ED_area_global_size_y(const ScrArea *area);
+int     ED_area_global_min_size_y(const ScrArea *area);
+int     ED_area_global_max_size_y(const ScrArea *area);
 bool    ED_area_is_global(const ScrArea *area);
 int     ED_region_global_size_y(void);
 void    ED_area_update_region_sizes(struct wmWindowManager *wm, struct wmWindow *win, struct ScrArea *area);
diff --git a/source/blender/editors/screen/area.c b/source/blender/editors/screen/area.c
index 16eeff01e58..e96580855d3 100644
--- a/source/blender/editors/screen/area.c
+++ b/source/blender/editors/screen/area.c
@@ -2362,6 +2362,16 @@ 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);
 }
+int ED_area_global_min_size_y(const ScrArea *area)
+{
+	BLI_assert(ED_area_is_global(area));
+	return round_fl_to_int(area->global->size_min * UI_DPI_FAC);
+}
+int ED_area_global_max_size_y(const ScrArea *area)
+{
+	BLI_assert(ED_area_is_global(area));
+	return round_fl_to_int(area->global->size_max * UI_DPI_FAC);
+}
 
 bool ED_area_is_global(const ScrArea *area)
 {
diff --git a/source/blender/editors/screen/screen_edit.c b/source/blender/editors/screen/screen_edit.c
index c3d18abc2cf..b3424ae3fb4 100644
--- a/source/blender/editors/screen/screen_edit.c
+++ b/source/blender/editors/screen/screen_edit.c
@@ -718,7 +718,7 @@ static void screen_vertices_scale(
 		/* adjust headery if verts are along the edge of window */
 		if (sa->v1->vec.y > window_rect->ymin)
 			headery += U.pixelsize;
-		if (sa->v2->vec.y < window_rect->ymax)
+		if (sa->v2->vec.y < (window_rect->ymax - 1))
 			headery += U.pixelsize;
 
 		if (area_geometry_height(sa) < headery) {
@@ -744,21 +744,32 @@ static void screen_vertices_scale(
 
 	/* Global areas have a fixed size that only changes with the DPI. Here we ensure that exactly this size is set. */
 	for (ScrArea *area = win->global_areas.areabase.first; area; area = area->next) {
+		int height = ED_area_global_size_y(area) - 1;
+
 		if (area->global->flag & GLOBAL_AREA_IS_HIDDEN) {
 			continue;
 		}
+
+		if (area->v1->vec.y > window_rect->ymin) {
+			height += U.pixelsize;
+		}
+		if (area->v2->vec.y < (window_rect->ymax - 1)) {
+			height += U.pixelsize;
+		}
+
 		/* width */
 		area->v1->vec.x = area->v2->vec.x = window_rect->xmin;
 		area->v3->vec.x = area->v4->vec.x = window_rect->xmax - 1;
 		/* height */
 		area->v1->vec.y = area->v4->vec.y = window_rect->ymin;
 		area->v2->vec.y = area->v3->vec.y = window_rect->ymax - 1;
+
 		switch (area->global->align) {
 			case GLOBAL_AREA_ALIGN_TOP:
-				area->v1->vec.y = area->v4->vec.y = area->v2->vec.y - ED_area_global_size_y(area);
+				area->v1->vec.y = area->v4->vec.y = area->v2->vec.y - height;
 				break;
 			case GLOBAL_AREA_ALIGN_BOTTOM:
-				area->v2->vec.y = area->v3->vec.y = area->v1->vec.y + ED_area_global_size_y(area);
+				area->v2->vec.y = area->v3->vec.y = area->v1->vec.y + height;
 				break;
 		}
 	}
diff --git a/source/blender/editors/screen/screen_ops.c b/source/blender/editors/screen/screen_ops.c
index e4de87e0b46..9c27bda5ec8 100644
--- a/source/blender/editors/screen/screen_ops.c
+++ b/source/blender/editors/screen/screen_ops.c
@@ -1235,8 +1235,8 @@ static void area_move_set_limits(
 	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);
+			const int size_min = ED_area_global_min_size_y(area) - 1;
+			const int size_max = ED_area_global_max_size_y(area) - 1;
 
 			/* logic here is only tested for lower edge :) */
 			/* left edge */
diff --git a/source/blender/windowmanager/intern/wm_window.c b/source/blender/windowmanager/intern/wm_window.c
index 7ca51724268..43231855162 100644
--- a/source/blender/windowmanager/intern/wm_window.c
+++ b/source/blender/windowmanager/intern/wm_window.c
@@ -2013,22 +2013,37 @@ void WM_window_rect_calc(const wmWindow *win, rcti *r_rect)
  */
 void WM_window_screen_rect_calc(const wmWindow *win, rcti *r_rect)
 {
-	rcti rect;
+	rcti window_rect, screen_rect;
 
-	BLI_rcti_init(&rect, 0, WM_window_pixels_x(win), 0, WM_window_pixels_y(win));
+	WM_window_rect_calc(win, &window_rect);
+	screen_rect = window_rect;
 
 	/* Substract global areas from screen rectangle. */
 	for (ScrArea *global_area = win->global_areas.areabase.first; global_area; global_area = global_area->next) {
+		int height = ED_area_global_size_y(global_area) - 1;
+
 		if (global_area->global->flag & GLOBAL_AREA_IS_HIDDEN) {
 			continue;
 		}
 
 		switch (global_area->global->align) {
 			case GLOBAL_AREA_ALIGN_TOP:
-				rect.ymax -= ED_area_global_size_y(global_area);
+				if ((screen_rect.ymax - height) > window_rect.ymin) {
+					height += U.pixelsize;
+				}
+				if (screen_rect.ymax < (window_rect.ymax - 1)) {
+					height += U.pixelsize;
+				}
+				screen_rect.ymax -= height;
 				break;
 			case GLOBAL_AREA_ALIGN_BOTTOM:
-				rect.ymin += ED_area_global_size_y(global_area);
+				if (screen_rect.ymin > window_rect.ymin) {
+					height += U.pixelsize;
+				}
+				if ((screen_rect.ymin + height) < (window_rect.ymax - 1)) {
+					height += U.pixelsize;
+				}
+				screen_rect.ymin += height;
 				break;
 			default:
 				BLI_assert(0);
@@ -2036,9 +2051,9 @@ void WM_window_screen_rect_calc(const wmWindow *win, rcti *r_rect)
 		}
 	}
 
-	BLI_assert(rect.xmin < rect.xmax);
-	BLI_assert(rect.ymin < rect.ymax);
-	*r_rect = rect;
+	BLI_assert(screen_rect.xmin < screen_rect.xmax);
+	BLI_assert(screen_rect.ymin < screen_rect.ymax);
+	*r_rect = screen_rect;
 }
 
 bool WM_window_is_fullscreen(wmWindow *win)