Passed it the day before Opera filed its complaint, too.

“With respect to standards and interoperability, our goal in developing Internet Explorer 8 is to support the right set of standards with excellent implementations and do so without breaking the existing Web,” Internet Explorer GM Dean Hachamovitch wrote in a post to IEBlog. “… We have a responsibility to respect the work that sites have already done to work with IE. We must deliver improved standards support and backwards compatibility so that IE8 (1) continues to work with the billions of pages on the web today that already work in IE6 and IE7 and (2) makes the development of the next billion pages, in an interoperable way, much easier. … Now, with all that context, I’m delighted to tell you that on Wednesday, Dec. 12, Internet Explorer correctly rendered the Acid2 page in IE8 standards mode.”

So much for Opera’s saber rattling …

Less than three months after agreeing to comply with key elements of the European Commission’s 2004 antitrust order against it, the company is facing new accusations of monopoly abuse. Norway’s Opera Software ASA said today it has filed an antitrust suit against Microsoft in the European Union, accusing it of stifling competition by tying its Internet Explorer Web browser to Windows and hindering interoperability by not implementing widely accepted Web standards.

“We are filing this complaint on behalf of all consumers who are tired of having a monopolist make choices for them,” Opera CEO Jon von Tetzchner said in a rather here-I-come-to-save-the-day statement. “In addition to promoting the free choice of individual consumers, we are a champion of open Web standards and cross-platform innovation. We cannot rest until we’ve brought fair and equitable options to consumers worldwide.”

And reminded the world that Opera is not just a drama set to music, but an unpopular Web browser, as well.

Opera asks that the EC’s competition division force Microsoft to unbundle IE from Windows and require the company to follow fundamental and open Web standards, which is an interesting twist on the old antitrust classic. And one that may have some legs, given IE’s inability to pass the Web Standards Project Acid2 test. “Microsoft often participates and even promises to support these standards, but we find it often isn’t the case,” Opera CTO Håkon Wium Lie told ZDNet. “We find bugs and programmers have to code around (Microsoft).”