Ensure all windows in OS Window are destroyed when OS Window is closed

kitty/boss.py

@@ -1817,13 +1817,15 @@ class Boss:
 
     def on_os_window_closed(self, os_window_id: int, viewport_width: int, viewport_height: int) -> None:
         self.cached_values['window-size'] = viewport_width, viewport_height
+        windows_in_os_window = {w.id: w for w in self.window_id_map.values() if w.os_window_id == os_window_id}
         tm = self.os_window_map.pop(os_window_id, None)
         if tm is not None:
-            tm.destroy()
-        for window_id in tuple(w.id for w in self.window_id_map.values() if w.os_window_id == os_window_id):
+            tm.destroy()  # this will call destroy on all windows
+        for window_id, w in windows_in_os_window.items():
             self.child_monitor.mark_for_close(window_id)
             self.window_id_map.pop(window_id, None)
             self.window_floats_map.pop(window_id, None)
+            w.destroy()  # in case tm was None
         if not self.os_window_map and is_macos:
             cocoa_set_menubar_title('')
         action = self.os_window_death_actions.pop(os_window_id, None)

kitty/window.py

@@ -1743,10 +1743,12 @@ class Window:
                 traceback.print_exc()
 
     def destroy(self) -> None:
+        if self.destroyed:
+            return
+        self.destroyed = True
         for cw in self.floats:
             cw.destroy()
         self.call_watchers(self.watchers.on_close, {})
-        self.destroyed = True
         self.clipboard_request_manager.close()
         del self.kitten_result_processors
         if hasattr(self, 'screen'):