i can't seem to get this addon to work on some type of rss feeds (extensionless rss file, with application/rss+xml type. can't set "open with firefox/librewolf" for that one in settings either). forcing the addon to be "enabled for all requests" still only opens the generic save dialog, and doesn't show this addon's options in regular window (but it ironically works fine in private window, however even using that to make it work doesn't help in regular browsing, despite being present in 'your saved MIME actions', not to mention my rss feed doesn't work in private browsing either, so i can't use that).

Looks bad for me, I guess because of using CustomCSSforFx.

This is one of my favorite extensions for Firefox, but it's having some problems with Firefox 57.0. It seems to behave badly on some pages that redirect you at load time (unfortunately, my best example so far is a company-internal page which I can't share). I'm also getting prompted twice now when downloading things -- once to present the traditional "Open with..."/"Open in browser as"/"Save File" dialog, and then again with another "Open with..." / "Save File" dialog.