I've recently looked into this for Ubuntu 24.04 LTS too.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/4546 is not
included in 48.6
In facts, it relies on some other API changes introducing
clutter_keymap_get_modifier_state():
* https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/4394
*
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/4395/diffs?commit_id=1940c6eba938a9413b93694573501153788d1f0f
These cannot be directly backported without breaking other consumers of
libmutter, like gnome-kiosk.
The fix description doesn't really explain why the previous approach
didn't work, so I also couldn't quite figure out how to fix it without
relying on the new API.
