struct { Object *stringobject; LONG success; }
in A1. The success parameter is a copy of the methods success parameter and indicates whether the popup was closed successfully (e.g. with a double click in a listview) or was just cancelled (e.g. by pressing the popup button again for toggle popups).
Due to internal message handling issues, calling the close hook is delayed until the next MUIM_HandleInput method is called. This allows you to remove and dispose windows without danger.