>George,
>
>Turn on event logging and checkout what's going on.
>
>It appears that the mousedrag operation that you are performing is triggering the ProgramaticChange event to fire even though the When() should have prevented anything from happening. The GotFocus() never fires so the cbo doesn't get focus, but the mouse*, click() and progchange events still fire. I think you could put conditional code into ProgramaticChange() and NODEFAULT under the same condition that causes the When to return .f. ala:
>
>

if ( ! thisform.editing )
>   nodefault
>endif

>
>
>>I would expect that the value of Combo1 cannot change, since the When( ) method returns false. This is not the case. The user can click on the center of Combo1, then drag out of Combo1 (either up or down). This changes the value, a little. Usually only a few values up or down.

David,

I agree with your assesment. However, I think what's going on is that the MouseOver event fires regardless of whether or not the When event executes. This is consistent with both what I know and have read about Combobox behavior.