Sorry for that, ashraf. The not-closing-issue is in fact a reported bug in the windows version of firefox >57.

The password is placed in any password field because of:
1. If you are opening the hasher with Ctrl-F6 before clicking on a password field, the hasher can't know which password-field has to be populated. (I'm lazy and don't want to leave my keyboard or stroking the tab 20 times before logging in...)
2. Some webpages are using invisible fields in the background to submit the password. If I only fll the obvious one, the password wont be submitted as the hidden one isn't populated.

Hope this is explaining the issues. Feel free to hook on the github-repository and donate some of your time by coding and bughunting... waiting for your pull-requests! ;-) Thanks!