plugin=diff is not implemented.
http://yellow.ribbon.to/~tuotehhou/index.php?%2BWinForm%2BVista%2FWindows%207%E3%81%AB%E3%81%8A%E3%81%91%E3%82%8BXP%E3%81%AEVisual%20Style%E3%81%AE%E5%88%A9%E7%94%A8
plugin=diff is not implemented.