>Leeroy,
>
>One surefire waay is to disable the launching mechanism when you start the form and reenable it when the form terminates. For example in a button click:
>
>

do form xyz with this && which is a subclass of SingleInstanceForm
>
>* SingleInstanceForm.Init
>lparameter roCallingObject
>
>this.oCaller = roCallingObject
>this.oCaller.Enabled = .f.
>
>* SingleInstanceForm.Destroy
>this.oCaller.Enabled = .t.
>this.oCaller = .null.
>

>

It seems more proper to me that the caller should disable itself, rather than asking the called form to do so. Of course, neither of these methods will work when the form can be called from multiple locations.

Chris.