>Does anyone know why the property thisform.ActiveControl (which should evaluate to the current control on the form) is invalid inside the QueryUnload event?

I'm Not sure but may be the object doesn't exist at this time ...

>I need to be able to determine the current control in order to validate that control. ( and posibly all parents). Note: the LostFocus (of any object) event is not called when the form is closed.

Look For destroy event !!!

Hope this help
Rocky Boy ...