Fred,

No, you can't do it in the BO.Destroy because that happens too late. The form already tried to Destroy and couldn't because of the outstanding reference. The order for .Destroy method firing is outer to inner, IE, the Form.Destroy executes first.

You either have to do in the Form.Destroy:
thisform.BO.oDataLayer = .NULL.

Or you can use BINDEVENT in the BO.Init to call some cleanup code in your BO:
*BO.Init:
BINDEVENT(thisform,"Destroy",this,"CleanUp",1)
*BO.CleanUp:
this.oDataLayer = .NULL.

At least that way the form doesn't have to know how to cleanup after other objects.

Still won't work.

Don't know if this may help: Since the form already disappeared but is still in the DataSession Window, I issued CLEAR ALL to clean up the mess. A few error messages come up, which basically is saying that it cannot find the BO's Alias property...

Thanks again.

Dennis