When I download a file in Firefox, I sometimes get an option to open or save the file, and once set, the default app to use to open the file stays set. But other filetypes only show a save option, even though I've set the filetype in Nemo to open correctly. I can't find any other place to set filetypes other than Firefox and Nemo properties.
If I download an NZB file, the dialog defaults to using SABnzbd, which is desirable. But if I download a .epub file, it only will save the file; I'd like it to open with Calibre ebook organizer, which it did on Ubuntu, my previous OS.