Paul,
There is a finite probabilty, depending on other events triggering in the environment, that _screen.ActiveForm might not be the calling form. If you explicitly pass a thisform reference down you are 100% guaranteed that you have the correct form.
>Thanks David for you help. your help assisted me in actually finding a similar but somewhat different way of doing it, from the kilofox book. i thought i would put it here in case anyone else wants to see it.