I have a VERY basic setup here. Running LB 13.8 (got my reasons) and just MAME (0.237), almost everything is default. Just using Esc to exit MAME.
I have this EXACT same setup on another machine, and everything works fine. For whatever reason, exiting a MAME game on this machine sends me back to Big Box, but I can't do anything because the focus is lost.
I have tried looking in task manager, alt+tabbing to see if there's anything else there, there's nothing. No other apps are running, nothing minimized, nothing in the background.
I do have a controller that has a mouse click type button on it, and if I push that button, it DOES regain focus. So I do have a work-around, but I'd love to just have it working normally.
I have read a bunch of other threads on the issue, but none seem to be the same. Big Box will launch fine, MAME will launch fine, can play the game without any problems, and closing MAME works fine, but Big Box just doesn't get its focus back. Even though I have this exact same setup (same LB version, same BB setup, same MAME version, same Windows 11 version) on another PC and it works fine.
I even used to have this controller plugged into the other machine that still works fine, so the controller doesn't seem to be the issue either.
Any ideas on what I can possibly look at to try and troubleshoot?