Autodesk does not support the Firefox browser for MapGuide. And yet, with Firefox's popularity people expect it to work and will try to use it with MapGuide. This discussion applies to all unsupported browsers, including Opera, Safari, Netscape 7, Mozilla, etc.
Firefox supports Netscape-style plugins unlike some of the other newer unsupported browsers. Therefore, a technically oriented user can download the MapGuide Netscape plug-in and install it in Firefox's plugin directory -- and voila! It (almost) works. In fact, it looks like it completely works because the map displays.
However, Firefox won't fully work with MapGuide because the MapGuide API does not work on this currently unsupported platform. As long as you use the Java Viewer or do a manual install of the plug-in, Firefox works pretty good except for the API. The Wrapper depends on the API to figure out what's installed and what to recommend to the user. Since the API doesn't work, the Wrapper really can't do it's thing with Firefox other than defaulting to the Java Viewer.
We considered adding support for Firefox and the plug-in, but didn't for some reasons noted in the code comments. First, the API doesn't work, but we thought we could just tell users to get the plugin. But then, you end up with an unsupported browser and one that doesn't work with the API. We now use the API with all our MapGuide maps. We don't want people to think that Firefox is a viable platform for MapGuide. Firefox is not viable for MapGuide until Autodesk does something to support it.