Windows 7 hasn't even been released in its final form but it has already drawn the ire of rival developers for its alleged anti-competitive behavior. If you’ve recently upgraded to the Release Candidate version of the OS from Vista rather than performing a fresh install, and chose the “express” option, you might have noticed how your default browser is reverted to Internet Explorer 8 regardless of your previous setting.

This of course has triggered new complaints from browser competitors that Microsoft is still abusing its dominant position to favor IE. Sure, there is also a “Custom” install option that lets users maintain their browser settings, but Opera and Mozilla argue that most users will opt for the easiest upgrade path – and they have reason to complain. The latest incarnation of Windows, although still in a test phase, has caught the attention of many and will be offered free to anyone for a full year.

Microsoft might change this rather dubious behavior when the final version of Windows 7 arrives, but at the very least it will help them regain some of their slipping market share in the meantime. The complaints are ill-timed for the software giant, however, as it faces a June antitrust hearing where it will defend itself against European Commission accusations that its practices are hurting alternative browsers.