Microsoft is citing its new interoperability initiative as the impetus behind the change. This move, designed primarily to stave off further EU intervention, emphasizes support and promotion of open standards in a way that the company hasn't previously done. This move should also help to stave off Opera's antitrust complaint, which argues that EU should force IE into better standards compliance.

While we do not believe any current legal requirements would dictate which rendering mode a browser must use, this step clearly removes this question as a potential legal and regulatory issue. As stated above, we think it?s the better choice.