scripts/startup/bl_operators/wm.py

@@ -3398,6 +3398,9 @@ class WM_MT_region_toggle_pie(Menu):
         region_by_type = {}
 
         for region in context.area.regions:
+            if region.poll_failed:
+                continue
+
             region_type = region.type
             attr = cls._region_info.get(region_type, None)
             if attr is None:

scripts/startup/bl_ui/space_view3d.py

@@ -1338,6 +1338,11 @@ class VIEW3D_MT_uv_map(Menu):
 
 # ********** View menus **********
 
+def asset_shelf_available(context):
+    for region in context.area.regions:
+        if region.type == 'ASSET_SHELF' and not region.poll_failed:
+            return True
+    return False
 
 class VIEW3D_MT_view(Menu):
     bl_label = "View"
@@ -1350,7 +1355,8 @@ class VIEW3D_MT_view(Menu):
         layout.prop(view, "show_region_toolbar")
         layout.prop(view, "show_region_ui")
         layout.prop(view, "show_region_tool_header")
-        layout.prop(view, "show_region_asset_shelf")
+        if asset_shelf_available(context):
+            layout.prop(view, "show_region_asset_shelf")
         layout.prop(view, "show_region_hud")
 
         layout.separator()

source/blender/makesrna/intern/rna_screen.cc

@@ -523,6 +523,12 @@ static void rna_def_region(BlenderRNA *brna)
   RNA_def_property_clear_flag(prop, PROP_EDITABLE);
   RNA_def_property_ui_text(prop, "Region Type", "Type of this region");
 
+  prop = RNA_def_property(srna, "poll_failed", PROP_BOOLEAN, PROP_NONE);
+  RNA_def_property_boolean_sdna(prop, nullptr, "flag", RGN_FLAG_POLL_FAILED);
+  RNA_def_property_ui_text(
+      prop, "", "If true, the region is not available in the current context");
+  RNA_def_property_clear_flag(prop, PROP_EDITABLE);
+
   prop = RNA_def_property(srna, "x", PROP_INT, PROP_NONE);
   RNA_def_property_int_sdna(prop, nullptr, "winrct.xmin");
   RNA_def_property_clear_flag(prop, PROP_EDITABLE);