Created attachment 149767 [details]
Example script, launching XMonad as the Window Manager
(Sorry if this is not in the right section, I'm not 100% sure where this bug falls)
In previous versions of KDE Plasma, setting the KDEWM environment variable to another Window Manager on your system would force Plasma to spawn that as the Window Manager in place of Kwin. Since 5.25, no matter what method is used to set the environment variable.
STEPS TO REPRODUCE
1. Install and set up an alternative Window Manager of choice for use with KDE Plasma (X11)
2. Set the KDEWM environment variable using a pre-startup script in ~/.config/plasma-workspace/env/
KDE Plasma spawns Kwin
KDE Plasma spawns the specified Window Manager
Linux/KDE Plasma: Arch Linux Rolling, all testing and unstable repo's enabled
Kernel version: 5.18.3-arch1-1
(available in About System)
KDE Plasma Version: 5.25.0
KDE Frameworks Version: 5.95.0
Qt Version: 5.15.4
(In reply to Adam Tazul from comment #0)
> Since 5.25, no matter what method is used to set the environment variable.
No matter what is set as KDEWM, it spawn Kwin instead of your WIndow Manager of choice***
Created attachment 149768 [details]
Example .desktop file from /usr/share/xsessions/, launching XMonad as the Window Manager
*** This bug has been marked as a duplicate of bug 439481 ***
(In reply to Antonio Rojas from comment #3)
> *** This bug has been marked as a duplicate of bug 439481 ***
These are not duplicates, as evidenced by the "steps to reproduce". In 439481 the environment variable KDEWM is not set, in this bug report it has been set, and as described by https://userbase.kde.org/Tutorials/Using_Other_Window_Managers_with_Plasma this should result in the specified binary being started instead of Kwin.
My bad upon further reading, it seems the issues are similar, though still a key difference in the use of systemdboot. I am to assume the KDEWM variable feature been silently removed?
(In reply to skeletonadventure from comment #5)
> My bad upon further reading, it seems the issues are similar, though still a
> key difference in the use of systemdboot.
It's not. You are using systemd boot because that's the default in 5.25.
(In reply to Antonio Rojas from comment #6)
> It's not. You are using systemd boot because that's the default in 5.25.
Shouldn't the KDEWM environment variable be read when using systemd boot?
Defaulting to systemd boot is a regression for any users of custom WMs. The update simply breaks the setup.
Also following the tutorial doesn't work anymore: https://userbase.kde.org/Tutorials/Using_Other_Window_Managers_with_Plasma
If KDEWM variable cannot be supported, there should be at least a guideline on how to use a custom WM with newer Plasma versions.
Instructions on how to run a custom WM with systemd boot enabled can be found in the Arch wiki: https://wiki.archlinux.org/title/KDE#Use_a_different_window_manager
TL;DR: Create a systemd user unit for your preferred WM and mask the kwin service.
This should be updated on https://userbase.kde.org/Tutorials/Using_Other_Window_Managers_with_Plasma.