fn transition_to_mouse_interaction_state(&mut self, new_state: MouseInteractionState) {
     ...
     if let MouseInteractionState::ShortcutHover(new_shortcut)
     | MouseInteractionState::ShortcutDrag(new_shortcut) = &new_state
     {
+        if exited_shortcut || entered_shortcut {
+            self.recompute_drawable_regions_in_rect(new_shortcut.frame());
+        }
     }
     ...
 }
 fn handle_mouse_moved(&mut self, _new_pos: Point, rel_shift: Point) {
    if let MouseInteractionState::ShortcutHover(shortcut) = &self.mouse_interaction_state
    {
+       self.recompute_drawable_regions_in_rect(shortcut.frame());
    } else if let MouseInteractionState::ShortcutDrag(shortcut) = &self.mouse_interaction_state {
+       self.queue_compositor_updates_for_old_and_new_element_frame(prev_frame, new_frame);
    }
 }