Garry's Mod (4000)

Compatibility Report

• Name of the game with compatibility issues: Garry's Mod x86_64 branch
• Steam AppID of the game: 4000

System Information

• GPU: 1050 Ti
• Driver/LLVM version: nvidia 430.26
• Kernel version: 5.1.15
• Link to full system information report as Gist: Here
• Proton version: 3.16-9 Beta

I confirm:

• [ X] that I haven't found an existing compatibility report for this game.
• [ X] that I have checked whether there are updates for my system available.

Symptoms

Game stuck on loading screen.

Reproduction

I found a error line in log:
7092.239:0024:0025:err:steamclient:create_win_interface Don't recognize interface name: SteamMatchGameSearch001

And i searched it. Seems it's fixed in newer version proton -here- but Proton 4.x which is doesn't include CEF patch. Proton developers merged this into -here- Proton 3.15+. Garry's Mod x86_64 uses Chromium Embedded Framework which is game need it to render html main menu and in-game things. (also i tried to play on Proton 4.x. Yes, game launched but CEF not worked as expected)

Log file

steam-4000.log

Start by reading the linked steam-4000.log and the compatibility report, then compare the reported behavior across the cited Proton versions and related issues. Done means Garry's Mod x86_64 gets past the loading screen and its Chromium Embedded Framework menu and in-game elements work as expected.