Then I created a second, non-admin user, giving that user all permissions seen in Control Center -> Users and Groups -> select the non-admin user -> Advanced Settings -> User Privileges tab -> ticked all checkboxes.
Then when I log in as the second, non-admin user using the x2go client, I get this networkmanager-related error (yet networkmanager applet still starts, it's just that when you click the applet ,"Enable Networking" and "Enable wifi" options are greyed out, although active, showing a checkmark beside them).
That dialog box wants the password for my admin user, not my non-admin user.
Can I make that error message not show upon x2go login? I would still like Networkmanager to start when the non-admin user logs in, because he/she might also possibly actually be sitting in front of the computer when they log in, not using x2go client.
Maybe this error has to do with running multiple instances of Networkmanager (both the admin user is logged in normally, then the non-admin user logs in also, using the x2goclient, and the 2nd user to start Networkmanager sees the error message). Maybe this error message has nothing to do with x2go per se.
Note that this error dialog (above) is not seen on Linux MInt Mate 19.2, when similarly logging in over x2go. But that experience isn't perfect either: the tray applet (panel applet)/notification area gets drawn funny . It's all garbled-looking. The rest of the desktop, and windows look fine, through x2go client, just not the panel applet/notification area. So in that respect, I actually recommend using Linux MInt MATE at this time, over Ubuntu MATE, if x2go is important to you.
...unless a solution to this problem can be found, with this error dialog popping up. Note, the applet/notification area in Ubuntu MATE 18.04 looks fine otherwise, it's not garbled, as it is in Linux Mint MATE 19.2.
