A quick little heads up if anyone is searching on this DROP problem. I had a LONG field I was using to display time duration with a DROP that showed a list of time strings as text ('10 minutes', '20 minutes', etc.) and their LONG equivalent as values (60000,120000). Worked fine in NT5 but with NT6 regardless of the choice made the result returned was always the first item on the list.
The problem was caused by the screen picture entry in the Data Dictionary (@T1 in this case). Change the picture to @Nx and the problem goes away