If the done signal is emitted by the common event handler, the window and all of its children have already been destroyed, so don't try to render with invalid renderer objects.
Right click to create new popup menus. Clicking over an existing popup menu will create a child menu. Left click to close all menus. Hover to display a tooltip that is the child of the window below it. Closing the application closes the root window, which should automatically destroy any open popup windows and exit gracefully.