Ahhh. As a first thought, that sounds like you could have restarted your desktop (eg logout -> login) without needing a reboot.
On a related topic, Ubuntu has an optional package that can be enabled to automatically restart the various systemd components that need it after their dependencies have been upgraded. From memory, that's specifically so people don't have to reboot unless it's really needed.
I don't remember the name of the package off hand though, but someone else here might... :)