The US Department of Justice (DoJ) and 17 states may seek court assistance following complaints a Windows XP feature, Shop Online for Music, fires-up Internet Explorer instead of a user’s chosen browser. IE takes users online to purchase CDs from retailers.

Any court case on the issue would represent the first legal test for Microsoft’s antitrust settlement, finally reached last year following a drawn-out legal process.

Microsoft’s record of antitrust compliance has been a mixed story. The company promptly delivered Windows XP Service Pack 1 (SP1) in 2002, enabling users and OEMs to hide offending middleware such as IE.

Release of Windows communications protocols has been a different matter, though. The company has twice substantially altered terms for access to Windows protocols under the Microsoft Communications Protocol Program (MCPP), following official disquiet. Microsoft eliminated non-disclosure agreements and cut the price in half to $50,000.

And this latest run-in is not limited to online music. Complaints have been received over the difficulty for end users in being able to purchase PCs, particularly laptops, from large OEMs without Windows pre-installed and the inability to disable Windows Messenger from launching instead of non-Microsoft middleware.

Windows Messenger was one piece of middleware that SP1 could hide.

Microsoft claim a provision of the antitrust settlement permits IE to become the default browser when there are certain technology requirements associated with the web site, such as use of ActiveX controls.

Microsoft is required to provide the technology requirements to other browser manufacturers on a by-request basis, although she was unsure whether ISVs had yet requested information.

This article was based on material originally published by ComputerWire.