You don't mention the version you upgraded from, however, my guess is that you leap frogged several versions during which (in order to maintain Windows 10 compatibility) TS started using Microsoft controls for pick list management where tabbing off a field does not select (your mouse or the enter key do).  RogerS may provide a KB articel # for your review but that is my guess about what is going on behind the scenes.

Allen, while I am aware that the "official" response from Sage is that this has to do with the new Microsoft controls, I respectfully disagree. 

What Richard is describing and what some of my upgraders are also suffering with is happening BEFORE he selects anything.  He's just trying to use the typing to get to the right entry.  So this would PREcede the control re: selecting of the entry once he gets there.

It is a problem, and saying its either A) not a problem, or B) is caused by a Microsoft control is not a sufficient response.

You are absolutely right Nancy

Actually Allen I was on site today with the client in question.  It works correctly everywhere else except the slip entry. E.g., entering a payment, client list, reprint bill images.  So it has something to do with the slip entry dialogue/look up.  It is driving my client up the wall!  Especially since it worked just fine in the old BDE version.

Hopefully they can tweak it the way they have optimized reports that have not performed as expected.