Changing bg color of an widget (Expander)

["Morten O. Hansen" <morteoh chello no>]

Hi,

I'm trying to change the bg color of a widget (gtk.Expander) to gray,
but I'm having trouble finding out where to do this. I see that
gtk.Widget.modify_bg is an option, but it doesn't work on widgets that
are inherited from gtk.Bin (there seems to be a workaround involving
gtk.EventBox, but I have no idea how to use this..)

Any good ideas how I can solve this? Is it possible something I can do
with gtk.Style?

With Regards, Morten O. Hansen