I am having multiple issues with the Game Pass for Windows 10 version of the Master Chief Collection relating to fullscreen mode.
Firstly, the game will not change to windowed when I apply the setting, the window will flash for an instant before reverting. Alt+Enter has a similar effect.
App notifications will not display over the game, and the game briefly freezes / goes to a black screen anytime I tab out of the game to access another app.
I have had similar issues with other Game Pass games, so I suspect it’s tied to games from that launcher. I have also tried disabling full screen optimization on the executable files, to no avail.
My specs are Intel i5 10300h, GTX 1650 and 8 GB RAM, but I have not had any other technical issues with running the game so I don’t believe it’s tied to that.