Norm,..

I have an I idea like this,..

If we call the form (with DO FORM ....) by menu I always give the menu's Skip For option like this :
assume that the form name is frmMyForm

WEXIST("frmMyform") OR WONTOP("frmMyForm")

so when the instance of form is still running your menu is Skipped (not Enabled).
We can implement this idea, if we call the form with other object simply change the command like this :
assume you call a form from command button object
in the command button's click or mouseup event I put this kind of code:

IF !WEXIST("frmMyform") OR !WONTOP("frmMyForm")
DO FORM frmMyform
ELSE
frmMyform.SHOW
ENDIF

But we can't do this if we call the form with other assigned variable like this :

DO FORM frmMyForm NAME frmOtherForm

'cause the instance form's name is different now,..
But I never use this kind of command I simply use DO FORM ....... directly.

OK, that's all just what I got now,...
Hope this will help
Thanks