User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:34.0) Gecko/20100101 Firefox/34.0 Build ID: 2014112600 Steps to reproduce: In application options for pdf, I have pdfs set to always ask, but when the open with dialog appears, there is no option for previewing in firefox, even though that is an option in the settings.

Isn't the dialog shown a dialog of your operating system? Wondering on which systems Firefox is registered as an application handling PDF files...

"open with" is an OS-provided file picker on Linux. I don't know why you wouldn't be able to select Firefox in it, but it's not our fault. :-) On Windows, it's a list we implement (using Windows' APIs). Either way, there is an entry in the dropdown for "Preview in Firefox" - why do we need to be in the "open with" list as well? Going to mark this as wontfix because of the previous paragraph.

(In reply to illumilor.e from comment #0) > User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:34.0) Gecko/20100101 > Firefox/34.0 > Build ID: 2014112600 > > Steps to reproduce: > > In application options for pdf, I have pdfs set to always ask, but when the > open with dialog appears, there is no option for previewing in firefox, even > though that is an option in the settings. I'm really sorry. I should have read better. You mean the download / open with dialog, not the preferences. Reopening.

Longing for this feature... (dup: 768788, 998475)