I've read a bunch of guides on how to use the "Prevent window deactivation function" but it seems to not work well for me. What I want to do is be in a game, alt+tab to the other monitor (where, say, a video is playing), change the said video and then alt tab right back to the game. However, when I do this it does not fully 'reconnect' back to the game. Often the mouse will work but I can't use any of the keys to move. Sometimes the mouse glitches out. Is there a way to set it up where I can just go back to the game by clicking on it like normal alt+tabbing with just one monitor?

With CS:GO, TF2, Everything I've tried so far. Essentially if I'm in a menu screen it works just fine as you'd expect and i can move the mouse straight to the other monitor but as soon as I am using something where the mouse is locked in like a first person shooter, it doesn't let me go to the other monitor unless I alt tab out of the game on the primary monitor. Also Firefox keeps opening up in the second monitor instead of the primary.

Edit - Alternatively is there a way I can use alt tab to just get the mouse on the second monitor and then alt tab back the the game on the first one?