Missing Panels In Mate and Gnome Shell

> I ran "sudo aptitude install trisquel-gnome" and said "Y" to the
> recommendation aptitude gave for install. Now my panel is gone in MATE.
> Also, I my "panel" is gone in my Gnome shell. What happened? How can I
> fix this?

I think that package might be left over from when GNOME 2 was Trisquel's
default desktop environment. I would get rid of it,

$ sudo apt purge trisquel-gnome

fix MATE,

$ sudo apt install trisquel

and install gnome

$ sudo apt install gnome

I ended up using synaptic to handle this. I had to reinstall those packages.