I use Gnome Shell on Ubuntu 11.10. I can use Gnome Tweak Tool to change the GTK theme and icon theme, but I can't change my window theme. If I select anything other than the default theme "Adwaita", and restart gnome shell, it reverts to the accessibility theme. How can I change the window/Metacity
Download a theme>extract it>Inside it should have something similar to this:
As you can see there's a gtk-3.0 and a metacity-1 folder. These two folders should be in: /home/user/.themes/.
Then open up Gnome Tweak Tool>go to Theme>Window theme>Scroll down to the theme you want.
Log out, and done.