Sets and clears _NET_WM_STATE_BELOW to lower and raise
the panel, enabling the use of _NET_WM_TYPE_DOCK, which
better describes the panel's purpose and fixes the
positioning issue with metacity.
_NET_WM_STATE_BELOW patch for rox (ROX-Filer) panel
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Should be tested with GTK+ 2.2 and 2.4.5 when released.