- User name.
- Search field. (end of tab sequence)
- (start of tab list) Browser address bar
The "Keep me logged in" checkbox and "Log in" button are not accessible through keyboard navigation.
I can consistently reproduce this in Safari 9.1.3 (latest stable), as well as in Safari Technology Preview Release 16 (Safari 10.1-alpha).
It seems this bug does not happen in latest Chrome or Firefox.