Comment 4 for bug 217507

some research brought me to gtk.Window.set_keep_below and gtk.Window.set_keep_above. I'm not sure whether set_keep_above needs explicitly to be false though. (checking gdesklets source, they're doing this reaaally complicated: they wrote a C-module which sends X events, I hope you won't need something like this as set_keep_below should do the same AFAICT).