Fired just before the parent form closes.
Parameters
None
Remarks
The OnParentClosing event fires just before the parent form (the form containing the Panel control) closes. This allows you to clean up anything before the window actually closes. For example, you could call RemoveForm to make sure everything is cleanly shutdown, since embedded forms can occasionally cause problems since OI assumes they are not children of other OI forms.
If you want to stop the parent from closing, then you must set the Cancel property to 1 during this event. This will only work if you qualify this event synchronously.
