Thanks a lot for your extensive explanation! I'll continue
experimenting with this additional information.
Groups are a way to track multiple versions from different projects
I guessed something like that. My expectation was, though, that all
languages would automatically be available in a group. Or at least
those that were available for any project in the group. But I
understand the intented behaviour is slightly different.
Yes, that tooltip is supposed to go away. If you could file a
bugzilla, it'll be greatly appreciated.