On my old XP computer, running an XBAP from Visual Studio would open it up in Google Chrome. I switched to Windows 7, and now running an XBAP downloads the file like it were
MIME Type Extension application/manifest .manifest application/x-ms-xbap .xbap application/octet-stream .deploy application/x-ms-application .application application/vnd.ms-xpsdocument .xps application/xaml+xml .xaml
Maybe it is related with the file extentsions?