Hello,

the current settings to select which users to display are not very practical when you want to propose just a few users ouf of the usual UID range... for Kali Linux we want to offer the possibility to login as root and I had to change MinimumUid to 0 and hide many users with something like this:

MinimumUid=0
HideShells=/bin/false,/usr/sbin/nologin,/bin/sync
HideUsers=arpwatch,speech-dispatcher,postgres

It would be nice to be able to just add "ShowUsers=root" in a configuration snippet stored in /etc/sddm/sddm.conf.d/ once #217 is implemented.