Problems with a Decky-Loader plugin in the latest versions of Proton

[stinga11]

Symptoms

Yesterday I updated to version 11.0-20260702 of proton-cachyos. With this version, the Decky-loader plugin, CheatDeck, no longer works. If I open any game in the gamescope-session and press the guide button, the game's trainer should appear, but nothing happens. If I open the game on the desktop and view the open windows with Alt+Tab, the trainer is running, but I can't access it. If I keep trying, a pop-up window appears asking me to force it to close or wait, but it gets stuck in an endless loop until I force it to close. I had to downgrade to version 11.0-20260602 because it works perfectly in that version, as it did in all previous versions of proton-cachyos. I've attached the log.

Steps to reproduce

1. Install Decky-Loader
2. Install CheatDeck by sheffeyG
3. Download any trainer from the flingtrainer website
4. Try to access the trainer.

Log from Proton-CachyOS 11.0-20260702 (CheatDeck Won't works)

11.0-20260702-steam-1593500.zip

Log from recent Proton-CachyOS 11.0-20260602 (CheatDeck Works)

11.0-20260602-steam-1593500.zip

EDIT:

Before assuming it is a proton-cachyos issue, note that it also happens with the latest version of Proton Experimental.

[SheffeyG]

Thanks for the report and logs.

In both enviroment logs, the trainer is successfully started before the game:

Loaded ... God of War v1.0-v1.0.2 Plus 15 Trainer.exe
Loaded ... GodOfWar\GoW.exe

This confirms that CheatDeck is setting PROTON_REMOTE_DEBUG_CMD correctly and that the new Proton-CachyOS version still supports it.

The issue appears to be related to window handling in newer Wine/Proton/Gamescope versions, and it is likely an upstream Proton or Wine regression problem.

Please consider reporting it to the Valve Proton issue with the two logs and the affected versions.

[stinga11]

Thanks for the report and logs.

In both enviroment logs, the trainer is successfully started before the game:

Loaded ... God of War v1.0-v1.0.2 Plus 15 Trainer.exe
Loaded ... GodOfWar\GoW.exe

This confirms that CheatDeck is setting PROTON_REMOTE_DEBUG_CMD correctly and that the new Proton-CachyOS version still supports it.

The issue appears to be related to window handling in newer Wine/Proton/Gamescope versions, and it is likely an upstream Proton or Wine regression problem.

Please consider reporting it to the Valve Proton issue with the two logs and the affected versions.

Thank you, I just submitted the report.

ValveSoftware/Proton#9999

[sunnynippo]

This seems to be an issue on Proton 11.0, experimental, hotfix and Proton-cachyos 11.0.
Ran the same on Proton 10.0-4 and Cheatdeck works fine and brings up the additional window.

I might try Proton-CachyOS 11.0-20260602 and see if it works.

Is there a workaround in the meantime to get this running on proton 11.0?

[Qiming-Liu]

Any updates for this? Does any new proton version fix it? Thanks 🙏

[stinga11]

Any updates for this? Does any new proton version fix it? Thanks 🙏

The problem is with Proton. I submitted a report on the Proton GitHub repository. You all need to start submitting reports because Valve is ignoring mine. We need to start complaining to see if they'll listen and fix it.