With recent changes, Clutter no longer sets up the viewport correctly,
unless it receives ConfigureNotify events. If there is a plugin with
an xevent_filter function, then it's that plugins responsibility to pass
the event to Clutter if it doesn't want it. If there is no plugin,
or the plugin doesn't have an xevent_filter function, then we should
call clutter_x11_handle_event() ourselves.
http://bugzilla.gnome.org/show_bug.cgi?id=589419
d91d503eb2
