Same problem. UNA-v.10.1.0 install, self hosted (Ubuntu 18.04 + LAMP) has been bugging me for some time how to I make another user Admin, Moderator etc.. but now I see why I couldn't find. Set Membership button is missing!!

The database fix didn't work for me?!

It gave the user more privileges but the Set Membership button still not there.

Any ideas??