Gnome Applet Menubar has unwanted focus rectangle

[Nigel Tao <nigel tao myrealbox com>]

I've recently written a small Gnome applet (announced on desktop-devel-
list) that consists of a single GtkMenuBar and it's children.
Everything is nice, except that (with the Glider theme) every so often
it gets an unwanted blue rectangle around the MenuBar - I suspect that
it is when the applet (or the MenuBar?  Menu?  MenuItem?) receives
focus.

A screenshot of the unwanted behavior is at
http://browserbookapp.sourceforge.net/bookmarks-focus-rectangle.png

Is there a way to get rid of the blue rectangle?  I have noticed that
the nearby "Applications Actions" Gnome menu applet does not appear to
be focusable - how do I set that?  I have unsuccessfully tried (in
PyGtk)
menubar.unset_flags(gtk.CAN_FOCUS)

tia,
Nigel.