Version 0.3, 10 January 2009, Owen Taylor.
Added the _NET_SYSTEM_TRAY_VISUAL hint and a description of visual and background pixmap handling.
Version 0.2, 23 November 2004, Mark McLoughlin.
Added the _NET_SYSTEM_TRAY_ORIENTATION hint.
Version 0.1, 20 April 2002, Havoc Pennington.
Created initial draft.