User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:14.0) Gecko/20100101 Firefox/14.0.1 Build ID: 20120713224749 Steps to reproduce: Clicked on http://distfiles.audacious-media-player.org/audacious-3.3.tar.bz2 Actual results: When clicking on a downloadable file, when the opening window comes up, the checkbox "do this automatically..." is greyed out for certain links. Furthermore, it always forgets what I opened with last. Expected results: FF should be able to remember choices for certain filetypes.

The "filetype" given by the server here is application/octet-strem Http headers send by the server for this URL: Status: HTTP/1.1 200 OK Server: nginx/1.2.1 Date: Sun, 29 Jul 2012 12:33:44 GMT Content-Type: application/octet-stream Content-Length: 456940 Last-Modified: Thu, 26 Jul 2012 23:45:50 GMT Connection: close Accept-Ranges: bytes The web doesn't use the file-extension as you might think but instead the content-type is used. application/content-stream is a general filetype for binary data and as such a file with this content-type can contain all kind of content. Remembering the choice for this content-type doesn't make sense. That you can't remember this decision is by intended (bug 189598)

What if when FF detects a generic content-stream it relies on the extension of the file for knowing what to do? Or at the very least, add the app that I opened it with last to the drop down menu so I don't have to type it in manually each time.

The database file (mimetypes.rdf) where the information about the saved decision are stored contains only content-type-> application entries. This is required because http relies on the content-type

So why not change it so that it can rely on filename extension if the content-type is generic?

There can easily be a setting where firefox checks to filename extension to guess at how to handle the file if the content-type is generic.