Account problem causing Settings Panel Problem

The Settings panel on my Windows 10 Pro production system opens full screen. I had another thread about the problem and with troubleshooting assistance the problem has been isolated to my Win 10 account. I can create another account and the Settings panel opens "normal" size. I dual boot the system with the Insider version and that version also opens "normal" size.

The problem started when I installed a video card (RX580) and moved from Intel CPU video to the new video card and 2560X1440 screen resolution (Windows recomended). If I select 1920X1080 (what I was using with the Intel Video) the Settings screen is the "norml" size.

I can't just create a new account and go from there, just as I've avoided a clean Win 10 install, because I will lose several of my recording studio add ons (that are no longer available due to the demise of then owned Gibson Brands "Sonar").

I suspect a registry entry is the cause of the Setting screen default size but I have no information on where or what the values should be. Just resizing the screen only works until its booted again (I wish it was that simple).

The Settings panel opening full screen is only a minor nuisance but I would like to get it resolved.

Lots of lookers but no suggestions, so far.