Seems like this doesn't have any relation to xrdesktop[1], which doesn't have mouse support! Really glad to see they have it here, any VR workspace is completely unusable if I have to use motion controls to simulate a mouse. Will definitely be trying this out tonight.
xrdesktop has a very talented team of hackers working on it (so I have no doubt they'll fix the mouse issue!).
Our approach with mouse cursors has been to assign every window its own mouse cursor. This is possible in Simula since the active window is the one that the user is currently gazing at, so that -- for example -- if you gaze at one window and move its cursor, it won't affect the other windows' cursors. We also allow users to control mouse cursors with their eye gaze (presently bounded to `Super + Apostrophe`), which is a good productivity boost.
In fact, you can do everything in Simula with just the keyboard (no mouse or VR controllers needed): move windows, move the mouse cursor, click the mouse cursor, etc. Once you learn the shortcuts, it's very quick.
[1] https://gitlab.freedesktop.org/xrdesktop/xrdesktop