Comment 15 for bug 651678

Edit on my post #14:
When restarting (relogingg?), a *file* ~/.gtkrc-2.0-kde4 is created with the following text inside:
include "/usr/share/themes/QtCurve/gtk-2.0/gtkrc"
If you delete it, it will be recreated on reboot.
The workaround I temporary use:
in the menu editor, replace the "evolution" command by the following:

rm -f ~/.gtkrc-2.0-kde4 && evolution