NB: beware of this bug!
Bug: gdm can't unlock desktop (after suspending, to switch users, etc)
Symptoms: lock screen takes very long (ie, a few seconds) to process username+password, returns “authentication error”, and becomes impossible to log in and unlock the screen again, with any user.
Failed to add watch on /run/systemd/ask-password: No space left on device
Annoyance: Gnome's top bar takes too much real state
gnome-shell-extension-autohidetopbar (may have dependencies), then configure
Workrave doesn't work