De este post na Comunidade Linux Mint:
"Gnome isn't extremely compatible with Linux Mint. It works but other operating systems probably work better. Ubuntu 14.04 for example. You can even download a gnome version for it. http://ubuntugnome.org/ Another operating system that is gnome-based is Fedora.
Also, I haven't managed to install extensions other than the ones through terminal below. I'm guessing it is possible but extra complicated than in the original gnome version.
Personally, I've removed gnome again, for now. I liked it, but it just isn't as compatible as I'd want it to be... By the way, when I installed gnome I installed it alongside cinnamon; I did not remove cinnamon."
É realmente necessário instalar o shell do gnome na sua construção do Mint? Parece que a dor não vale a pena.