Mate Desktop gone on 18.04. How to get it back?

Hi there, I have an old development machine that runs Ubuntu Mate 18.04, but due to old libraries that I need to reference I am stuck at that version on that box. It is on a Dell laptop, and I recently was able to get RDP working on it, so I can remote into it and use it from another machine. That works great, and I have the Mate desktop there in its glory.

But in the process of setting up the desktop for my RDP login, I must have butchered the normal desktop on the laptop, as it now appears to be a Gnome desktop of some form, with no title bar, etc. I login to the laptop using my local account there and I login to the RDP session using the same account, but by RDP. RDP is fine but the local login on the machine is the problem child here - that's the one that doesn't show the Mate desktop.

Is there a setting I can change here to force it to use the Mate desktop on all logins?

Thanks in advance for any help here.


from a terminal, mate-panel --replace