I've installed tightvncserver together with ubuntu-mate desktop on a headless server. Everything works perfect now, but i can't really change user permission inside of ubuntu-mate. Normally i could go to the user manager and set the account type to administrator, custom or a desktop user etc. But i'm not allowed to change this. Not even when i login as root, which i know is not secure. I read it has something to do with a bug in the user manager, that's not going to be repared. But still i need to give users desktop account types, to disallow them to change settings etc.
How do i give myself admin privileges and other users some basic permissions for using the remote desktop for what they need to use it for? Because i really need some more control inside of ubuntu-mate desktop to do this.
I did try to use the console and at my linux users to sudo, using:
sudo usermod -ag sudo username
But there is no change inside ubuntu user manager and all users have custom account type by default... So no success. Any other commands i could use? Any hints or tips are welcome.