Hide UI is broken - Can someone help ?

[💛🐠Schluppdidupp🍀🍄]

When I just started the game and wanted to hide the UI for taking screenshots, I hit the usual Strg + Shift + U which was working perfectly when I played last time (which was last week). I bought the Fancy Dress DLC afterwards (also last week) and now wanted to check it out. So I changed the dress of a staff member and when I wanted to take a screenshot and hit Strg +Shift + U , I ended up on the desktop which was huge. Hitting Esc made the desktop normal again but the same 3 keys that still worked last week perfectly, suddenly no longer work. So I removed the tick in the properties, went back, tried again but it's the same thing. Then I sent the last savegame from last week to the folder of the PC, started the game and tried another time but it's still the same. I then started the game on my old PC and there, it worked correctly immediately with Ctrl+Shift+U , I also tried various other things but nothing would work. The problem is only here on my new PC but until this 24th June, it all worked perfectly and suddenly no longer when I wanted to play again a few days later.

What happened ??? Is there another way to hide the UI ?

I don't play with mods, have only some wallpapers and floors from the workshop which never caused me any problems and until last week, all was fine. So this can't be the reason.