What happens when you open them off the desktop?
That's independent of your desktop configuration, unfortunately, since Firefox keeps its own list of mime types ([1]). Came across the following post in the Ubuntu forums: http://ubuntuforums.org/showpost.php?p=5641587&postcount=11 The file $HOME/.mozilla/firefox/<random_sequence>.default/mimeTyptes.rdf contains all the mime types: http://kb.mozillazine.org/MimeTypes.rdf According to the mozillazine article, the file gets automatically created if missing. So, here's what I'd do: 1. Close Firefox. 2. Rename the mimeTypes.rdf file to mimeTypes.rdf.old 3. Restart Firefox. 4. Test double-clicking on a downloaded PDF in the download manager. Cheers, Peter References: [1] http://en.wikipedia.org/wiki/MIME_type [2] http://ubuntuforums.org/showpost.php?p=5641587&postcount=11 [3] http://kb.mozillazine.org/MimeTypes.rdf -- Peter Reutemann, Dept. of Computer Science, University of Waikato, NZ http://www.cs.waikato.ac.nz/~fracpete/ Ph. +64 (7) 858-5174