Hello @MichelN86, we're using one issue report per unofficially supported game title, so I've gone ahead and transferred this issue report to https://github.com/ValveSoftware/Proton/issues/782#issuecomment-3534072406.
I ran into the bug again, this time with proton 9.0-4. When i alt tab out of the game and go back to the game the screen will go into windowed mode, when i change the setting from windowed to fullscreen it started to happen. The screen is set to fullscreen BUT the mousemovement is out of place. Like it is using the smaller screen from windowed mode and the mouse barely moves. I think this deserves a new ticket/bug report.
proton 9.0-4x2 2025-11proton 10.0-3x1 2025-11
Compatibility Report
System Information
I confirm:
Symptoms
The game for first look looks like it is working till you get into the main menu, the mouse barly moves and it feels like it can´t go to the right. It's moving very slow. Proton 10.0-3 has a bug, proton 9.0-4 is working fine for this game.
Reproduction
See symptoms.