The answer here should be very similar to the one I gave on Ask Ubuntu regarding WSLg and Xfce4.
WSGg uses Wayland/Weston/Xwayland (via RDP extensions and a separate Mariner "System" distro) to display GUI apps in Windows 11.
The Weston Window Manager is already running in the current Wayland session, so it's difficult to launch a separate fullscreen desktop/window manager over the top of that.
The solution here seems to be the same as for Xfce4 -- Launch a fullscreen Xwayland session. While it will be running under WSLg's Weston instance, it can have its own desktop and window manager.
Assuming you are on Ubuntu (which I am assuming, since you posted there), first:
sudo apt install xwayland
I've updated my launch technique for desktops under WSLg's Xwayland slightly since my Ask Ubuntu answer. I currently recommend creating something like:
Xwayland :1 &
WAYLAND_DISPLAY= DISPLAY=:1 startlxqt
A few important notes:
I'm assuming that you installed the
openbox package when installing LxQt. If not, make sure you do, and select it as your window manager when launching LxQt for the first time.
It's really important to remember that a lot of desktop services rely on either Systemd or physical hardware that might not exist in WSL2 (or both). You may run into issues with some features as a result.
I run into a regular issue when Alt-tabbing (Windows) between Windows Terminal and Xwayland where mouse clicks won't register. Tapping the Alt key, the Shift key, and the Ctrl key (not together) seems to "unstick" whatever is causing the problem.