Microsoft's recent decision to ship its upcoming Internet Explorer (IE) 8.0 browser with Web standards-based rendering enabled by default doesn't fully answer the complaints that browser competitor Opera has expressed to antitrust regulators in the European Union (EU), according to Opera CTO Hakon Wium Lie. His company has outlined a set of technical concerns that he thinks the EU should force Microsoft to address. One of the concerns is that IE 8.0 should fully comply with the Acid2 standards test.

"IE 8.0, by supporting Acid2 and triggering standards mode like other browsers, partly addresses [our complaints]," he said. "But the other points remain."

The other points include Microsoft documenting IE's support of standards, supporting standards that are also supported by two or more browser competitors, and documenting how its browsers do pass the Acid2 test, if they do. Opera's complaint, which echoes the US antitrust suit against Microsoft almost a decade ago, alleges that Microsoft's bundling of IE with Windows is illegal.

In announcing its decision to ship IE 8.0 with a default Web standards rendering mode last week (a move that reversed an earlier decision not to do so), Microsoft specifically noted the legal ramifications of this change of heart. "While we do not believe there are currently any legal requirements that would dictate which rendering mode must be chosen as the default for a given browser," said Brad Smith, Microsoft's senior vice president and general counsel, at the time, "this step clearly removes this question as a potential legal and regulatory issue."

Microsoft is eager to put its antitrust problems behind it. Unfortunately, Opera and other Microsoft competitors have found eager and willing compatriots in the EU's European Commission, which has opened three new antitrust investigations against the software giant over the past several months.