window.c: Drop the toolkit grab when we start a compositor grab

We do this right for move and resize, but dnd and popups need the same
treatment.

clients/dnd.c

@@ -402,6 +402,8 @@ dnd_button_handler(struct widget *widget,
 		dnd_drag->drag_surface =
 			wl_compositor_create_surface(compositor);
 
+		input_ungrab(input);
+
 		dnd_drag->data_source =
 			display_create_data_source(dnd->display);
 		wl_data_source_add_listener(dnd_drag->data_source,

clients/window.c

@@ -2391,6 +2391,7 @@ window_show_menu(struct display *display,
 	window->x = x;
 	window->y = y;
 
+	input_ungrab(input);
 	wl_shell_surface_set_popup(window->shell_surface, input->input_device,
 				   display_get_serial(window->display),
 				   window->parent->shell_surface,