I'm stuck trying to figure out how to get a Gdk::Window from a Gtk::Window.You should be able to use Gtk::Widget::get_window(). This will return NULL before the widget is realized, but after it is realized it should return a valid Gdk::Window.
That seems to work, I wasn't all that clear on how the inheritance worked between Gtk::Window and Gtk::Widget.
Yes, this seems like a case where the the C documentation was not customized correctly for the C++ API. I think you should be able to pass a 'NULL' RefPtr<Pixmap> to this parameter and it should work. e.g. Glib::RefPtr<Pixmap> none; w->set_back_pixmap(none ...) I haven't tested it to make sure though. here's a bug I filed for the issue: http://bugzilla.gnome.org/show_bug.cgi?id=525967
Yes, that syntax does appear to work as you've indicated in the bug, but I agree that a dedicated unset_* function would be a lot more intuitive!
Thanks for your help! Cheers, Adam.