All my menus are highlighted like in the attached image.
I asked around and someone told me my gtk theme might be broken. However, I have no clue how to fix it. This occurs on my system menus, DE changer in the login menu, and most other programs.
As I commented, an update brakes compatibility with Themes.
So you'll have to remove the Gnome 3 Team PPA and the Ricotz testing PPA then downgrade the packages to the Ubuntu version.
Install ppa -purge to make this easier.
In my case, for Unity I fixed this problem by deleting
With Xfce, I had this problem when using Settings / Appearance / ambiance-xfce-lxde theme that I got from http://www.ravefinity.com/p/ambiance-radiance-for-xfce-lxde.html
For Xfce, I fixed this by making a new theme with everything else from Ambiance, but the gtk-2.0 folder from ambiance-xfce-lxde:
and then selecting MyAmbiance from Settings / Appearance.