Problem with CheckMenuItem::set_inconsistent

[John Spray <jcspray icculus org>]

I'm trying to create a CheckMenuItem with the 'inconsistent' state.  The
following code snippet pops up the menu with the item, but the item
appears in the inactive state, as if set_inconsistent hadn't been
called.  Waiting until after popup() to call set_inconsistent (so that
the checkmenuitem is realized) makes no difference.  The same sort of
thing on a usual CheckButton works fine.

Suggestions?

John

void popup ()
{
  Gtk::Menu *menu = Gtk::manage(new Gtk::Menu);

  Gtk::CheckMenuItem *item = Gtk::manage(new Gtk::CheckMenuItem("Foo"));
  item->set_inconsistent (true);
  menu->append (*item);
  menu->show_all ();
  menu->popup (0, 0);
}