I made a newbie mistake though and accidentally switched to Adwaita in the gnome shell appearance manager and now, it's mixing up my UI.
Basically, my windows look like adwaita and not the "hacktivist" theme I have installed on the bottom panel.

It's annoying. I think it's switched to my Mate/Gnome3 icon theme too, instead of the hacktivist theme.
Any ideas on how to fix this?
I'm using mint 12, 64bit on an Asus laptop, if that helps.
The settings:

I really do apologize. I was the idiot who looked the wrong place first and didn't read how to mess with themes properly. HM.