plugin=diff is not implemented.
http://yellow.ribbon.to/~tuotehhou/index.php?%2BSL%2B%E5%8B%95%E7%9A%84%E3%81%AB%E3%82%BB%E3%83%AB%E3%82%92%E6%8F%8F%E7%94%BB%E3%81%99%E3%82%8B
plugin=diff is not implemented.