In 12.04 Ambiance theme, the default right click menu color changed from black to white.
From this bug-report, it appears this decision is by design
But I love black only. How can I change it to black?
Stan Angeloff has created a theme that requires the use of ubuntu-tweak or gnome-tweak-tool (i used the former) to enable. Check this link:
Ok here's the modified Ambiance theme for 12.04
Extract it in
home/username/.themes/. Use gnome-tweak-tools to change the theme.
Problem solved ;)
Now I suggest you use deviant-art to find a window theme that looks like Ambiance but has a black right-click menu I was able to find color versions of these themes at this link http://ubuntu-art.org/content/show.php?content=147891 but it will take some work finding an older version of Ambiance with this customization unless the Ubuntu community does something to change it for Precise.
If you have never changed a custom theme follow this link
As per omgubuntu
you can use this tweaked ambiance for 12.04
To make use of Ambiance Oneiric hit the button above to download the .zip file. Then extract the .zip archive in to the ‘.themes’ folder in your Home directory (tip: you’ll need to press CTRL+H to reveal hidden files).
Then apply the theme use myunity
it will definitly work if you edit /usr/share/themes/Ambiance/gtk-3.0/gtk.css file because all theme colors rendered from that file but to do that you need to be root
gksu gedit /usr/share/themes/Ambiance/gtk-3.0/gtk.css