When I have Minecraft 1.18 open and I use another launcher to record my games, before some update, I would press ALT + TAB, and switch to the open program for recording and I could play minecraft while recording, now instead of opening the alt+ menu tab, you'll lose focus on the full screen app (meaning you can't interact with that window), but you can't see what's below it because it's full screen and stays in the foreground