I got fed up with Unity and decided to switch to Xubuntu, following the instructions on this thread. Almost everything went well, and I'm much happier with the system. However the window borders from the Unity theme are still being used, overriding the Xubuntu themes.
I've uninstalled all the Unity stuff that I can find. I have, however, kept Compiz for some of its functionality. I note that if I disable the "Window Decoration" plugin the whole border disappears leaving nothing behind.
I want to have normal Xubuntu borders. Note that applications like Chromium which handle their own borders display correctly.
I'll gladly give more details, or upload screenshots. Just let me know what information would be helpful.