The Commission has initiated formal investigation proceedings against Microsoft in two cases following complaints from the European Committee for Interoperable Systems (ECIS) and Opera (another browser vendor). Both complaints allege that Microsoft has abused a dominant position in the market contrary to Article 82. ECIS’s complaint concerns refusal to disclose interoperability information and Opera has alleged that by tying its Internet Explorer product to its Windows operating system Microsoft is hindering access to competitors. The Commission has indicated that it will assess the complaints in line with the principles confirmed by the CFI in the 2007 Microsoft Judgment, upholding the Commission’s 2004 Article 82 infringement decision against Microsoft.