I had maverick and I have customized Ambiance theme to have light background color for tooltips. But from Natty onwards I can't see the 'Customize' button anywhere. How can I customize the themes in some user friendly way?
Sadly, there is no "user friendly" way anymore. Gnome 3 doesnt come with a "gnome-appearance-properties"..
What you can do is make your own theme .. (I know ..) or tweak already existing themes. Even harder now, you have gtk2 and gtk3 themes to tweak...
For example, Ambiance: Copy paste '/usr/share/themes/Ambiance' to '~/.themes/My_Ambiance'.
Edit colors (ie #FFFFFF, #??????) in '~/.themes/My_Ambiance/gtk-3.0/gtk.css' AND '~/.themes/My_Ambiance/gtk-2.0/gtkrc'.
Changing tooltip_bg_color and tooltip_fg_color in both files should work for you.
You can use
To apply your "new" theme, you can use myunity (in the repo). You might have to restart X to see the changes.
PS: That's no anwser to your question (NOT USER FRIENDLY) but it was to big to post as a comment.