Some applications are displaying really ugly widgets and menus. I think it's a GTK issue and perhaps more particularly, only applies to GTK2 apps but I'm not sure. The numerous questions on here that deal with GTK2 v GTK3 themes do not answer my problem. Here is my situation:

• I'm using Ubuntu Gnome with Gnome Shell (installed using the "upgrade" instructions, rather than fresh install) with the default Adwaita theme
• The reason I did an upgrade instead of fresh install is because I'm on a Macbook Air and there is no mac image/iso for Ubuntu Gnome
• Previously, I did a fresh install of Ubuntu Gnome 12.10 and had no theming problems
• Now, apps like nautilus, rhythmbox, brasero, even third-party ones like Lightread look exactly as expected but other apps, including Firefox, Inkscape, GIMP, Libreoffice look awful.
• Some examples:
  • Firefox with ugly location bar: http://ubuntuone.com/3e2X0JTa4CT4afC4303U9c vs nautilus location bar: http://ubuntuone.com/3TbHWWuNMcJnlpI4IpjiUO
  • GIMP file dialogue (like Windows 95!): http://ubuntuone.com/4ioCcqq3flgO7zAWgAhfWy vs the rhythmbox file dialogue (correct): http://ubuntuone.com/2xLplCOBvQnyeqdsTGdgXq
  • Menus in Libreoffice (very bad for usability): http://ubuntuone.com/26WTaEz4PMGmiItGeSmBjZ vs menus in rhythmbox: http://ubuntuone.com/4Ib4thMLqohsle6J5KEvuI

I've been searching for a solution to this problem for some time. The logical explanation is that all the GTK3 apps are working and anything that is still using GTK2 is not. If that's the case though, why did the same installation (Ubuntu Gnome 12.10) and the same theme (Adwaita) previously work with all those GTK2 apps?

Desperate for help!