Tested with Evolution-1.0.1-2 and the gtk+ pixmap theme "Smoke". In previous versions of Evolution, the mailer table titles had backgrounds using the theme. Starting with Evolution 1.0.1, they are now using a lighter grey color that makes them stand out from everything else and look misplaced. Will attach a screenshot.
Created attachment 42755 [details] Screenshot showing the light-grey colored title background
This was an intentional change to gal because gal doesn't really completely handle everything related to themes and so wasn't changing text color properly iirc. WONTFIX'ing it here, but feel free to file upstream in bugzilla.ximian.com if you feel strongly about it, although I bet that it won't really be looked at much until the gnome2 port when they'll have to properly respect themes for a11y.