Whenever I click a download link in Firefox (Ffox 38, on Ubuntu 12.04LTS) such as a PDF, I get
And there's nothing more sensible than GVim in the Open With menu.
When I look in about:preferences, I see
Which seems to imply it's aware of a document viewer application, but then it's not giving me that option when it opens a PDF...?
I've used PDF here as an example, it's the same with other formats, e.g. it also offers to open tar files with Gvim...
How can I get Firefox 38 to correctly populate the Open with drop-down?
(nb. I'm aware that this has been asked before but those solutions only work for earlier versions of Firefox, so are irrelevant.)
EDIT: To be clear, my desktop system (Gnome Shell) does not have a problem opening files; it's just Firefox.
$ xdg-mime query default application/pdf evince.desktop