(Proton 9 and Experimental) Mouse clicks don't work in games when I have a higher resolution primary monitor next to a lower resolution secondary monitor.

[BugsyReportsy]

Your system information

• Steam client version (build number or date): 1723685248
• Distribution (e.g. Ubuntu): Linux Mint 22 (Ubuntu)
• Opted into Steam client beta?: [Yes]
• Have you checked for system updates?: [Yes]
• Steam Logs: steam-logs.tar.gz
• GPU: Nvidia RTX 3050 4GB

Please describe your issue in as much detail as possible:

Mouse clicks won't work in games when using my normal monitor setup, where I have a higher resolution 4K TV to the right of my lower resolution 1080p laptop display. I suspect this has to do with my main monitor being a higher resolution than my secondary one, because when I lowered my primary's resolution to 1440p the mouse inputs worked but was noticeably misaligned with the cursor, and when I set both's resoluton to 1080p the mouse worked as intended. I found a stop-gap solution to this problem by having my secondary display below my primary one while maintaining its 4K resolution.

I discovered this bug when I launched UltraKill with Proton but was unable to click anything on the main menu. When I launched TF2 and Operation: Harsh Doorstop to test if this issue applied to other games, I found that TF2, a native game, worked properly, while Operation: Harsh Doorstop, running through Proton, had similar issues to UltraKill. The issues still apply regardless if I was using a Bluetooth, 2.4ghz, wired, or even a Steam Input joystick mouse.

Steps for reproducing this issue:

1. Have a monitor arrangement where there's a 4K/higher resolution primary display next to a 1080p/substantially lower resolution secondary display.
2. Launch a game through Steam and Proton 9, UltraKill and Operation: Harsh Doorstop in this case.
3. Test the mouse inputs by trying to click every button on screen.

[RW74]

Hi, it seems a common issue since version 9 at least, I do have the same scenario and I have the external bigger resolution monitor on my right (1440p). for me a workaround was to setup the left monitor as primary but I have the disadvantage that some games take as reference the primary monitor resolution (1080p) and even if the mouse interact with the game properly on the secondary monitor, it only work with a resolution up to 1080p (like MSFS 2020).

7717

7550

[Draconicrose]

I'm having this, or at least a similar issue, as well.

I have a 1440p monitor as my main monitor, and a 1280x1024 monitor as my secondary. The primary is connected to an NVIDIA gpu while the secondary is connected to an intel igpu.

When the secondary is to the left of the primary, proton will not let my mouse go to the right of the middle of the primary screen, almost as if it was detecting the edge of the monitor instead of the middle. In some games, the mouse can move around the screen freely, but inputs won't register to the right of the middle of the screen.

If I move the secondary monitor (in display settings, not physically) to the right of the primary monitor these behaviors go away. I didn't try moving it above or below the primary.

This behavior seems present in any proton version above 9 so far.

And, finally, my system for completion's sake: https://termbin.com/a79c (LM 22, Nvidia + intel gpus)