Sorry, that’s just plain confusing, but as I said before mainly cosmetic. It’s the same Samba, but how it reacts with the Software Center is different.
If I install a Domain first, via the left sidebar, it installs Samba, but leaves it as “installable” from the Software Center. Except it isn’t:
If, instead of creating the Domain first, you install Samba from the Software Center and then create the Domain, that uninstalls the Samba you installed, and re-installs it:
I didn’t think to check if any configuration was made to the original Samba before creating the Domain, that it’s retained across the re-install.
Cheers.