Keep/lock mouse to fullscreen app/game (multi-monitor problem on KDE) [window rules]

Hi, I’m having problems with mouse focus on my multi-monitor setup in some games (Insurgency: Sandstorm & V Rising).
It seems that I leave the full screen window with the mouse cursor in the middle of the game and click something on the other monitor, and then lose game focus as a consequence.
This is very annoying especially in competitive games.

I tried to fix that problem with a window rule but I had no success so far.


AFAIK this rule should fix my problem with Insurgency: Sandstorm but it still occurs.


Hi, I am still looking for a solution to my problem. I’ve edited my first post a bit to make it clearer.

I’ve also discovered a program called Gamescope that can fix this problem, among others, but unfortunately it does not run with my Nvidia card (enabled “nvidia-drm.modeset=1”). Seems I experience the same issue described here.

I also found a tool named Jail which I’ll try later out. Hoping it is the solution.