plugin=diff is not implemented.
http://yellow.ribbon.to/~tuotehhou/index.php?%2BVSTO%2BRibbon%20%E8%AA%AD%E3%81%BF%E8%BE%BC%E3%82%80%E9%9A%9B%E3%81%AE%E9%A0%86%E7%95%AA
plugin=diff is not implemented.