plugin=diff is not implemented.
http://yellow.ribbon.to/~tuotehhou/index.php?%2BCA%2B2011%E5%B9%B407%E6%9C%8803%E6%97%A5%20Ver%201.1.3%20%E3%83%AA%E3%83%AA%E3%83%BC%E3%82%B9
plugin=diff is not implemented.