I know, this topic was here before.... but none of the suggestions helped and I'm confused, I don't know what I am missing. But lets begin.
I have a Ubuntu 11.10 which was upgraded by all those years from 8.04 so It's kind of old, but all works fine except theme.
Right after install all looked great but after one of updates (don't know which) theme got crappy. Let's start with lightdm. It looks fine, but settings button is not transparent (it has common GT border) and password entry box is not rounded. Instead of dots to mask password I see '*'. Well I think this is a small problem, the bigger one are the menus. Also context menus are the same, other menus looks ok.
After I login unity starts and looks.... well as it should look. But expanding any menu from notification area (including user switch and system menu) spoils that effect. I have a strange theme on those menus. Light gray background, darker gray text (almost unreadable) and black separators/inactive items. Selection looks normal (orange bg/white text)
There is also one more strange thing. Menus from nautilus are under title bar instead on unity panel (I have reinstalled appmenu-gtk3 appmenu-gtk appmenu-qt)
I can post screens, but I think I covered all in text.
I've tried reinstalling theme packages, after that changing theme with advanced configuration util. This didn't help so I've reinstalled unity and still nothing.
Reinstaling unity menus also did not help. Editing some flags in gconf editor provided some results, but.... rather for worse. My theme looks like on screens below (done with my phone.... login screen doesn't have prtscr handling, and when menu is open for some reason ptrscr also doesn't work)