[proton#4270] Possible wrong DISPLAY env var inside the new container when using Wayland

This is the issue that has been reported upstream https://github.com/ValveSoftware/Proton/issues/4270

From the testing that I performed this is what I experienced so far:

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When I use an X11 env it works without any issues.

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In a Wayland env I'm currently unable to launch any games (e.g. Fall Guys 1097150). This issue seems to be related to the environment variables locking patch !134 (merged), because if I replace pressure-vessel with an older build, it works. I'm currently trying to find which environment variables might be the problem here.

UPDATE: it seems to be caused by an issue with the DISPLAY var. A fix has been proposed here !155 (merged)

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Then the third scenario is when you install SLR Soldier, close and reopen Steam. With SLR Soldier already installed at Steam startup, when I try to launch a game it seems like pressure-vessel is not executed at all, SLR Soldier is not touched. I even tried moving the directory SteamLinuxRuntime_soldier and the error was exactly the same, no complains about the missing Soldier. This leads to the game being launched incorrectly, and the proton log file will contain the errors reported upstream:

1959.828:0020:00a4:err:winediag:nodrv_CreateWindow Application tried to create a window, but no driver could be loaded.
1959.828:0020:00a4:err:winediag:nodrv_CreateWindow Make sure that your X server is running and that $DISPLAY is set correctly.

UPDATE: this issue was caused by an old soldier.vdf file that I had in my compatibilitytools.d directory. It's unlikely to be related to the upstream proton#4266. I fixed it by simply removing this vdf file that I previously created.