Gets the Thumbnail Toolbar button ID that is clicked.
HRESULT value = object.get_buttonID(* p);
the numeric ID of the button that is clicked.
This event is fired when a user clicks a custom button in a Thumbnail Toolbar that pinned site adds with msSiteModeAddThumbBarButton. The button ID that this event returns is the same that is returned when the button was added.
Build date: 11/17/2013