--- a/src/xfns.c
+++ b/src/xfns.c
@@ -5054,7 +5054,7 @@ struct mouse_cursor_data {
   int menu_bar_height = 0, menu_bar_width = 0;
   int tool_bar_height = 0, tool_bar_width = 0;
 
-  if (FRAME_INITIAL_P (f) || !FRAME_X_P (f))
+  if (FRAME_INITIAL_P (f) || !FRAME_X_P (f) || !FRAME_OUTER_WINDOW (f))
     return Qnil;
 
   block_input ();