Sequencer: ensure Strip is the default active panel

source/blender/blenloader/intern/versioning_defaults.c

@@ -159,13 +159,16 @@ void BLO_update_defaults_startup_blend(Main *bmain, const char *app_template)
   for (bScreen *screen = bmain->screens.first; screen; screen = screen->id.next) {
     for (ScrArea *sa = screen->areabase.first; sa; sa = sa->next) {
       for (ARegion *ar = sa->regionbase.first; ar; ar = ar->next) {
-        /* Remove all stored panels, we want to use defaults
-         * (order, open/closed) as defined by UI code here! */
-        BKE_area_region_panels_free(&ar->panels);
+        if (builtin_template) {
+          /* Remove all stored panels, we want to use defaults
+           * (order, open/closed) as defined by UI code here! */
+          BKE_area_region_panels_free(&ar->panels);
+          BLI_freelistN(&ar->panels_category_active);
 
-        /* Reset size so it uses consistent defaults from the region types. */
-        ar->sizex = 0;
-        ar->sizey = 0;
+          /* Reset size so it uses consistent defaults from the region types. */
+          ar->sizex = 0;
+          ar->sizey = 0;
+        }
 
         /* some toolbars have been saved as initialized,
          * we don't want them to have odd zoom-level or scrolling set, see: T47047 */

source/blender/editors/include/UI_interface.h

@@ -1641,6 +1641,7 @@ struct PanelCategoryDyn *UI_panel_category_find(struct ARegion *ar, const char *
 struct PanelCategoryStack *UI_panel_category_active_find(struct ARegion *ar, const char *idname);
 const char *UI_panel_category_active_get(struct ARegion *ar, bool set_fallback);
 void UI_panel_category_active_set(struct ARegion *ar, const char *idname);
+void UI_panel_category_active_set_default(struct ARegion *ar, const char *idname);
 struct PanelCategoryDyn *UI_panel_category_find_mouse_over_ex(struct ARegion *ar,
                                                               const int x,
                                                               const int y);

source/blender/editors/interface/interface_panel.c

@@ -1676,28 +1676,7 @@ PanelCategoryStack *UI_panel_category_active_find(ARegion *ar, const char *idnam
   return BLI_findstring(&ar->panels_category_active, idname, offsetof(PanelCategoryStack, idname));
 }
 
-const char *UI_panel_category_active_get(ARegion *ar, bool set_fallback)
-{
-  PanelCategoryStack *pc_act;
-
-  for (pc_act = ar->panels_category_active.first; pc_act; pc_act = pc_act->next) {
-    if (UI_panel_category_find(ar, pc_act->idname)) {
-      return pc_act->idname;
-    }
-  }
-
-  if (set_fallback) {
-    PanelCategoryDyn *pc_dyn = ar->panels_category.first;
-    if (pc_dyn) {
-      UI_panel_category_active_set(ar, pc_dyn->idname);
-      return pc_dyn->idname;
-    }
-  }
-
-  return NULL;
-}
-
-void UI_panel_category_active_set(ARegion *ar, const char *idname)
+static void ui_panel_category_active_set(ARegion *ar, const char *idname, bool fallback)
 {
   ListBase *lb = &ar->panels_category_active;
   PanelCategoryStack *pc_act = UI_panel_category_active_find(ar, idname);
@@ -1710,7 +1689,13 @@ void UI_panel_category_active_set(ARegion *ar, const char *idname)
     BLI_strncpy(pc_act->idname, idname, sizeof(pc_act->idname));
   }
 
-  BLI_addhead(lb, pc_act);
+  if (fallback) {
+    /* For fallbacks, add at the end so explicitly chosen categories have priority. */
+    BLI_addtail(lb, pc_act);
+  }
+  else {
+    BLI_addhead(lb, pc_act);
+  }
 
   /* validate all active panels, we could do this on load,
    * they are harmless - but we should remove somewhere.
@@ -1729,6 +1714,39 @@ void UI_panel_category_active_set(ARegion *ar, const char *idname)
   }
 }
 
+void UI_panel_category_active_set(ARegion *ar, const char *idname)
+{
+  ui_panel_category_active_set(ar, idname, false);
+}
+
+void UI_panel_category_active_set_default(ARegion *ar, const char *idname)
+{
+  if (!UI_panel_category_active_find(ar, idname)) {
+    ui_panel_category_active_set(ar, idname, true);
+  }
+}
+
+const char *UI_panel_category_active_get(ARegion *ar, bool set_fallback)
+{
+  PanelCategoryStack *pc_act;
+
+  for (pc_act = ar->panels_category_active.first; pc_act; pc_act = pc_act->next) {
+    if (UI_panel_category_find(ar, pc_act->idname)) {
+      return pc_act->idname;
+    }
+  }
+
+  if (set_fallback) {
+    PanelCategoryDyn *pc_dyn = ar->panels_category.first;
+    if (pc_dyn) {
+      ui_panel_category_active_set(ar, pc_dyn->idname, true);
+      return pc_dyn->idname;
+    }
+  }
+
+  return NULL;
+}
+
 PanelCategoryDyn *UI_panel_category_find_mouse_over_ex(ARegion *ar, const int x, const int y)
 {
   PanelCategoryDyn *ptd;

source/blender/editors/space_sequencer/space_sequencer.c

@@ -729,6 +729,7 @@ static void sequencer_buttons_region_init(wmWindowManager *wm, ARegion *ar)
   keymap = WM_keymap_ensure(wm->defaultconf, "SequencerCommon", SPACE_SEQ, 0);
   WM_event_add_keymap_handler_v2d_mask(&ar->handlers, keymap);
 
+  UI_panel_category_active_set_default(ar, "Strip");
   ED_region_panels_init(wm, ar);
 }