Huh?!?!? Microsoft fostering competition?!?

Microsoft is offering space to help the Mozilla folks make Firefox, their browser, work on Vista (as well as Thunderbird, their e-mail client, but the browser has significantly more market share). I really want to know WHY on earth they would do this. No one would notice if MS didn't invite Mozilla to their developer conference, and the fact that they did just makes no sense. Firefox has made one of the most successful challenges to Microsoft's market dominance in years, stealing 15% of Internet Explorer's pageviews in just 2 years. Microsoft is overhauling IE for the first time in years, and I wonder why they would help the competition for their new browser. I have only a few ideas on why they would do this. 1) It's highly unlikely, but they could give the Mozilla coders deliberate mis-information, resulting in Firefox for Vista having inferior performance. This is more a crazy conspiracy theory than anything else - it would be too easy to discover, and too hard to actually accomplish (where is the line between code that is slow, and code that is non-functional?) 2) Microsoft could want something to point to as a symbol when the anti-trust folks come around again, suing them for abuse of their monopoly. This seems the most likely option I can think of. 3) Or maybe Microsoft really is committed to fostering competition. History would contradict this view though, so very few people would be that charitable towards MS.