> I found WorkUnitNumber is never decremented so the form is not close when

the Finish button or Cancel button clicked.

>
> How about if I add Dec(FWorkUnitNumber) in TfrmBase.AfterCompleteWorkUnit

? Is this correct (it's work for me, form is close) ? Or is it by design ?

By design.

WorkUnitNumber isn't a increment/decrement reference tracking mechanism. It
is merely intended to distinguish one work flow item from subsequent ones.
It just increments indefinitely. I suppose if a user sat in front of it long
enough to do two billion work items we might exhaust its range of values but
I don't expect that to be an immediate concern.

Jason Wharton
CPS - Mesa AZ
http://www.ibobjects.com