Vista - How do I use custom background color / theme?

I like to use a custom background color in windows. In Windows XP I just
need to change background color windows and everything works. Explorer,
notepad, wordpad, word use custom background color.

Vista is different. I made the same change it has lesser effect. Some
background are affected and some are not. Example is Mail. Tree control
still uses white background, while the rest of the window seems to have
adapted my color.

Is there something to change the rest of the colors? Something like free
theme editor. Is it just an xml file I can change?


Thanks