plugin=diff is not implemented.
http://yellow.ribbon.to/~tuotehhou/index.php?%2BCA%2B2011%E5%B9%B410%E6%9C%8809%E6%97%A5%20Ver%201.3.0%20%E3%83%AA%E3%83%AA%E3%83%BC%E3%82%B9
plugin=diff is not implemented.