chromium gtk theme has wrong colours

Attached is a screenshort of a side-by-side comparison with another GTK app, Tomboy, which provides the expected result from the QtCurve theme ( http://goo.gl/T1knU ).

Even more strangely the window background colour changes when the window goes out of focus. Another screenshot to illustrate:

http://i45.tinypic.com/ksscw.png

I searched for information and came up with this:

https://code.google.com/p/chromium/wiki/LinuxGtkThemeIntegration

I'm not too clear on the specifics (not the most technical of users here, I'm afraid) but apparently Chromium needs those colours specified in a particular way, otherwise it does an imprecise "best guess" which may or may not work.

So I don't -think- it's an issue specific to this theme, rather that the theme's particular colour selection makes it easier to notice.