Re: Firefox already does what he asked
"If someone got to my desktop it is NOT too late anyway, because these are passwords to sites where other information is available. You like to surrender info?"
I do agree for the main part - which is why I voted that this is a bug and needs to be fixed: Password visibility arguably means all they need is a brief access to nab that data, which is why I voted for that option, but consider that if someone has managed to nab your computer and accessed your user account, they don't actually need to see the passwords: they can just visit the sites using your browser with its saved passwords.
Which means that on a shared computer, where the owners
are too stupid or lazy to don't have separate, password protected user accounts, and/or don't log out of their account when they're finished there is no real protection anyway, password-protected passwords or not.
This is arguably why there needs to be a lot more user education.
My real vote would be "This is a bug that needs to be fixed (from the third option), but non-techie people won't realise and need to be educated (from the second)."
I was tempted to add don't leave your computer and unlocked from the first, but sometimes that is necessary when people like me need to fix other people's computers - but that would often be prevented if users were better educated to start with.
The problem with arguing that users need to be better educated, though, is that many users don't want to be educated.