[AccessD] Access 2007 "On Click" Event on Tab (Page) - Never Fired???

I have a very simple test Form with 2 Tabs (Page1 and Page2).

In the Property Sheet for both Page1 and Page2, I see an "On Click"
event.

However, when I add a MSGBOX to the Event Procedure, it appears that the
event is never fired.

I must be missing something.

Thanks,

Brad