Atop the new investigation into Microsoft's failure to give some Windows users a browser ballot screen, European Union (EU) antitrust officials are also looking into charges that Microsoft has blocked rival browser makers from harnessing the power of Windows 8 for their software, according to the Reuters news service.
Earlier Wednesday, Reuters reported that the European Commission had launched an inquest into accusations that Microsoft stymies other browser makers' efforts to build software that runs in Windows 8 and the offshoot designed for ARM-powered tablets, Windows RT.
The new investigation is part of the one the Commission opened Tuesday, when it said Microsoft broke a three-year-old agreement by failing to supply a "browser choice" screen to customers running Windows 7 Service Pack 1 (SP1).
According to Reuters, a Commission spokesman confirmed that antitrust officials are also looking into allegations that Microsoft refuses to give rivals full access to APIs (application programming interface) in both Windows 8 and Windows RT.
The Windows RT APIs have been the source of tension between Microsoft on one hand, and Mozilla and Google on the other.
Two months ago, Mozilla's lead lawyer and one of its Firefox directors accused Microsoft of withholding APIs necessary to build a competitive browser for Windows RT, and said the behavior "may have antitrust implications."
Those Mozilla officials noted that Microsoft has given full API access only to the latter's own Internet Explorer 10 (IE10), the sole browser that will run on Windows RT's conventional desktop. Also, sans those APIs, it will be impossible to create a viable Metro-style browser for Windows RT, Mozilla has contended.
"We could build a beautiful Firefox that looked really nice on Metro, but Firefox would be so crippled in terms of power and speed that it's probably not worth it to even bother," said Asa Dotzler, director of Firefox, at the time.
Google said it "share[ed] the concerns Mozilla has raised" when the issue came up two months ago.
Microsoft previously declined comment about the Mozilla and Google complaints, and did not reply today to a request for comment on the Reuters report.
Reuters also said that the Commission is investigating charges that Microsoft "does not provide full access to complete APIs for non-default browsers in Windows 8."
Those APIs, which have not been a major bone of contention, likely are ones that block any browser's Metro version from running in Windows 8's tile-based environment unless that browser has been designated as the default by the user.
Windows 8 initially sets IE10 as the default browser in both Metro and the traditional desktop, the two different -- and some say "jarring" -- modes in the operating system.
In other words, only one Metro browser may run at a time.
According to Reuters, the Commission's newest investigation was kick-started by complaints filed by other companies. A Commission spokesman declined to identify those firms to Reuters.
Mozilla and Google did not reply to requests for comment on the new investigation. Computerworld is awaiting confirmation on the Reuters report from the Commission.
European antitrust regulators have made it clear that Windows 8 must abide by the 2009 deal that requires the operating system to offer users a choice of browsers other than IE. The officials, however, have declined to say whether the same also applies to Windows RT.
By the language of the landmark settlement Microsoft reached in 2002 with the U.S. Department of Justice, Microsoft may be free to ban access to Win32 APIs in Windows RT, as the settlement repeatedly limited the deal to "Intel-compatible PCs."
U.S. government scrutiny of Microsoft ended in 2007.
Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at @gkeizer, on Google+ or subscribe to Gregg's RSS feed. His email address is [email protected].
Read more about drm and legal issues in Computerworld's DRM and Legal Issues Topic Center.