I can confirm this. But, please consider dupe-ing your bug to the one you mentioned and posting a comment mentioning that this affects groups too. This really is the same problem with the "Show All" checkbox being removed.
** Changed in: gnome-system-tools (Ubuntu)
Status: Unconfirmed => Confirmed
--
[user-admin] some groups are hidden
https://launchpad.net/bugs/78888
--
ubuntu-bugs mailing list
[email protected]
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
