European antitrust officials have widened their investigation into Microsoft's browser practices to include four different allegations against Windows 8 and Windows RT, a government spokesman said Wednesday.
Antoine Colombani from the European Commission's antitrust agency confirmed that the inquest, originally opened Tuesday to look into Windows 7, has expanded to cover accusations leveled at Windows 8 and Windows RT.
Reuters first reported some of the new claims early Tuesday.
"We will indeed look at these allegations made by third parties in the context of the investigation opened yesterday on Microsoft's compliance with our December 2009 decision," said Colombani in an email reply to questions Wednesday.
Two of the charges raised by outsiders -- which the commission would not name -- had been reported by Reuters, and revolve around APIs (application programming interfaces) in Windows 8 and Windows RT that Microsoft has allegedly withheld from rival browser makers.
Windows RT has garnered the most attention, as Mozilla and Google have expressed frustration over Microsoft's policy of blocking access to special APIs in that edition. Mozilla has claimed that without those APIs, it cannot build a browser competitive with Internet Explorer 10 (IE10) on tablets.
The Windows 8 APIs relate to what Colombani called "non-default browsers in Windows 8." Although he did not elaborate, Colombani may have been referring to a Windows 8 practice that prevents a browser's Metro version from running unless its desktop edition has been designated by the user as the system default.
Microsoft sets IE10 as the default browser in Windows 8. Users can change the default, but they may not know where the option is located.
Additionally, said Colombani, the commission is scrutinizing two other allegations.
One relates to Microsoft's practice of providing co-marketing funds to OEMs, or original equipment manufacturers, such as Dell, Hewlett-Packard and Lenovo.
"Third parties allege that Microsoft is acting in violation of the browser commitments by discouraging computer manufacturers (OEMs) by means of payments or withholding payments under marketing programmes from setting third-party browsers as default in Windows 8," Colombani said.