The "save password" dialog disappears before I can click it.
Since a few weeks, on both my computers (running Firefox 44.0.2 in Fedora 23) the "save password" dialog has stopped being useful. For some reason, it shows up and then disappears as soon as the page reloads (which is normal, when you log in). I thought at first it was only on pages with fancy redirects / ajax logins, but it even happens on very simple websites (for example mailman logins etc.). Restarting with add-ons disabled doesn't address the issue.
Alla svar (3)
Did you look for a Key icon at the left end of the location/address bar?
See also:
You know, on many websites that actually solves my problem. Thanks! But this cannot be the intended behavior, right? To quickly flash a dialog at me with buttons I can never press? Fields I can never edit? And then somehow I need to know about this tiny button? What happened here that this suddenly became necessary?
You're welcome.
I don't know what will cause that doorhanger to close, probably only the Firefox developers know all those details. A plugin that takes focus or JavaScript (AJAX) that updates some content could be possible candidates.