Was working on a production issue so I had to step away from this problem for a week. Now I have some bits of free time again so I'm looking for a solution.
System is Xeon based with a Radeon 3900 FireGL workstation card. No Catalyst or other special software is loaded, just the minimum AMD drivers and those are now 3 years out of date (v9.11) but we are not allowed to touch the O/S in any way, cannot download anything, and most of the commands that require admin rights are locked so we can't use them. As an example, even though we paid for the full lifetime licensing for our UltraEdit software I am only allowed to request through IT Support that the software be upgraded every 18-24 months. That is why we went from v17 to v21.00 (I actually asked for the upgrade when v19 came out but IT was so busy it took months to fill my request and v20 came out only a few days before IT scheduled the update). The only reason I got v21.20 on my computer was that we activated a couple of unused licenses for new employees and they wanted us to be uniform so they moved all of the accounts to v21.20 instead of having a mix of v21.00 and v21.20 We'll most likely not have V22 on any of our computers ever, but I hope that we will catch up with v23 when it comes out.
So I did some more tests and created up to 5 extra instances of UltraEdit running at the same time. The original UE window opens on the right side monitor in the same size as it was the session before. The second UE opens on the left monitor, centered and about 800x600 resolution. Third, fourth, and fifth windows all open on the right side, same size as the second UE and each is mostly centered on the right monitor but four is 20 pixels to the right and 20 pixels down from three while five is 20 more pixels to the right but 40 pixels up from four.
So just for a test I closed all instances of UE, opened the uedit324.in0 file and manually changed the values for the window position, making it larger and moving it to the left monitor. When I opened 5 extra instances of UE, the fourth window opened on the left hand monitor but still in the small size it had before. But after closing and reopening it was back to the right side monitor and centered again.
So I did another test. I deleted all of the UEdit321-325 files and then created 5 extra UE sessions. Again the second UE opened on the left monitor while all of the rest opened on the right monitor. The screens were all 800x600 size and sessions 2 through 5 all opened in the same place without any pixel offset. So I closed them all again. Reopened - all exactly appeared in the same place and size as before. Resized them to various sizes and moved them around. Closed all of them and then reopened them. All of the extra sessions went back to 800x600 size, but for sessions 2 through 5 the upper left location was where I moved the windows to the time before.
So I can get UE to remember where to place the window on the right side monitor, I just can't get UE to remember the size of the window for any instance except the first session, and I can't get the second session to load anywhere on the left monitor except centered. If I move the second session to the right side monitor, then the next time it opens up it opens at the height of the previous session but centered side to side and once again at 800x600.