Hi Jimmy.

>> need the previous stocknumber so that I can find it in the inventory table and clear the transaction number. Once I do that, I can requery and the old product no longer shows up related to this transaction. <<

Add a customer property to your combo class called uOldVal. In the GotFocus of the combo, put code like this:

This.uOldVal = This.Value

Then, in the combo's valid, you can decide whether or not the user selected a new stock number like so and takle appropriate action:

IF .ListIndex > 0
  IF IsNull( .uOldVal ) OR ( .uOldVal # .Value )
    *** The user selected a different product...take action
  ENDIF	
ENDIF

HTH

Marcia