BUG: panel doesn't change bgcolor

[Richard Hult <rhult hem2 passagen se>]

When switching themes, the panel doesn't change it's background color,
even though it's set for "default background". If you switch theme and
then go to "this panel prop..." and change to black for example and
then back to "default", then it gets the right themed bgcolor.

(Latest cvs everything, RH5.2)

Regards,
Richard