Firefox 3.0 XmlHttpRequest Default Content-Type change

I ran into a small problem with some of my AJAX code that's checking content-type on inbound requests from the client - it looks like FireFox 3.0 is now including the charset on the content type from the client on POST operations which if not explicitly checked for can break existing code expecting only to see a content type. Small issue, but easy to miss especially in framework code like mine that frankly should have been prepared for this...