plugin=diff is not implemented.
http://yellow.ribbon.to/~tuotehhou/index.php?%2BWPF%2B%E3%82%B9%E3%82%BF%E3%82%A4%E3%83%AB%E3%83%95%E3%82%A1%E3%82%A4%E3%83%AB%E3%81%AE%E5%AE%9A%E7%BE%A9
plugin=diff is not implemented.