After playing once in VR, "regular mode" will no longer go full screen.

[Spinnetti]

I've had all the IL2 versions since the beginning, and have all but Normandy now. I got some VR goggles and played both Great Battles and Tank Crew in VR. I went to play the "normal" version and it wouldn't go full screen. I tried changing resolution, selecting and deselecting full screen and restarting etc, rebooting and trying it all again etc. It plays fine, but only in a window even with full screen checked. Anything I should look for? I don't know if its anything related to VR, but its the only thing I think I've changed lately. If I change to native resolution, it works fine and is of course full screen, but not at anything less. It works ok with maxxed out graphics still, but my full rez is 5k, so a bit of a load on the machine and I generally prefer to run at 1440p rather than 2880.