Comment 3 for bug 189037

Had my friend Ryan Paul look at this and he came up with this patch, which "works for me".

He sends along a "if he really does need to use gtk.Fixed and manually set the width/height of self.vbox, that he should use get_monitor_geometry for the active monitor rather than using screen_width() and screen_height()"

Hope this works for you! (bzr bundle attached)