I just upgraded to a new Mac and a newer OS X release than I previously was running and have encountered some different behaviour in Safari 8 that I can't turn off around offering to save passwords.
In Safari 7 you could disable auto-fill for passwords which would stop Safari ever prompting you per How to completely disable password saving in Safari which is what I had done in the past.
However with Safari 8 the preferences pane looks slightly different and frustratingly enough the relevant option is greyed out and there is no obvious way to disable it:
Any idea how I can disable this behaviour under Safari 8?