Fix tool not being initialized switching windows

source/blender/blenloader/intern/readfile.c

@@ -6729,6 +6729,8 @@ static void direct_link_area(FileData *fd, ScrArea *area)
 	area->butspacetype = SPACE_EMPTY; /* Should always be unset so that rna_Area_type_get works correctly */
 	area->region_active_win = -1;
 
+	area->flag &= ~AREA_FLAG_ACTIVE_TOOL_UPDATE;
+
 	area->global = newdataadr(fd, area->global);
 
 	/* if we do not have the spacetype registered we cannot

source/blender/editors/screen/area.c

@@ -1639,7 +1639,11 @@ void ED_area_initialize(wmWindowManager *wm, wmWindow *win, ScrArea *sa)
 		region_azones_add(screen, sa, ar, ar->alignment & ~RGN_SPLIT_PREV);
 	}
 
-	WM_toolsystem_refresh_screen_area(workspace, view_layer, sa);
+
+	if ((1 << sa->spacetype) & WM_TOOLSYSTEM_SPACE_MASK) {
+		WM_toolsystem_refresh_screen_area(workspace, view_layer, sa);
+		sa->flag |= AREA_FLAG_ACTIVE_TOOL_UPDATE;
+	}
 }
 
 static void region_update_rect(ARegion *ar)

source/blender/makesdna/DNA_screen_types.h

@@ -368,7 +368,7 @@ enum {
 #endif
 	/* update size of regions within the area */
 	AREA_FLAG_REGION_SIZE_UPDATE = (1 << 3),
-//	AREA_FLAG_DEPRECATED_4       = (1 << 4),
+	AREA_FLAG_ACTIVE_TOOL_UPDATE = (1 << 4),
 //	AREA_FLAG_DEPRECATED_5       = (1 << 5),
 	/* used to check if we should switch back to prevspace (of a different type) */
 	AREA_FLAG_TEMP_TYPE          = (1 << 6),

source/blender/windowmanager/WM_toolsystem.h

@@ -86,11 +86,11 @@ int WM_toolsystem_mode_from_spacetype(
         struct ViewLayer *view_layer, struct ScrArea *sa, int space_type);
 bool WM_toolsystem_key_from_context(
         struct ViewLayer *view_layer, struct ScrArea *sa, bToolKey *tkey);
-void WM_toolsystem_update_from_context(
-        struct bContext *C,
-        struct WorkSpace *workspace, struct Scene *scene, struct ScrArea *sa);
 
 void WM_toolsystem_update_from_context_view3d(struct bContext *C);
+void WM_toolsystem_update_from_context(
+        struct bContext *C, struct WorkSpace *workspace, struct ViewLayer *view_layer,
+        struct ScrArea *sa);
 
 bool WM_toolsystem_active_tool_is_brush(const struct bContext *C);
 

source/blender/windowmanager/intern/wm_draw.c

@@ -73,6 +73,7 @@
 
 #include "WM_api.h"
 #include "WM_types.h"
+#include "WM_toolsystem.h"
 #include "wm.h"
 #include "wm_draw.h"
 #include "wm_window.h"
@@ -542,6 +543,11 @@ static void wm_draw_window_offscreen(bContext *C, wmWindow *win, bool stereo)
 
 		ED_area_update_region_sizes(wm, win, sa);
 
+		if (sa->flag & AREA_FLAG_ACTIVE_TOOL_UPDATE) {
+			WM_toolsystem_update_from_context(C, CTX_wm_workspace(C), CTX_data_view_layer(C), sa);
+			sa->flag &= ~AREA_FLAG_ACTIVE_TOOL_UPDATE;
+		}
+
 		/* Then do actual drawing of regions. */
 		for (ARegion *ar = sa->regionbase.first; ar; ar = ar->next) {
 			if (ar->visible && ar->do_draw) {

source/blender/windowmanager/intern/wm_toolsystem.c

@@ -851,6 +851,18 @@ void WM_toolsystem_update_from_context_view3d(bContext *C)
 	toolsystem_reinit_ensure_toolref(C, workspace, &tkey, NULL);
 }
 
+void WM_toolsystem_update_from_context(
+        bContext *C, WorkSpace *workspace, ViewLayer *view_layer,
+        ScrArea *sa)
+{
+	const bToolKey tkey = {
+		.space_type = sa->spacetype,
+		.mode = WM_toolsystem_mode_from_spacetype(view_layer, sa, sa->spacetype),
+	};
+	toolsystem_reinit_ensure_toolref(C, workspace, &tkey, NULL);
+}
+
+
 /**
  * For paint modes to support non-brush tools.
  */