The order of events when closing a form is:

FORM.QUERYUNLOAD
FORM.DESTROY
FORM.CONTAINER.DESTROY
FORM.CONTAINER.COMMAND.DESTROY
FORM.UNLOAD

We have code in the UNLOAD as follows:

SELECT Covr
IF CURSORGETPROP( 'Buffering' ) > 1 AND ! TABLEUPDATE( .T. )
	TABLEREVERT( .T. )
ENDIF 
CURSORSETPROP("Buffering",1)

But we are getting an error in the DESTROY that there are uncommitted changes to Covr. What happens by default in the DESTROY that would cause this?