Hello,
>From memory (so take it with a grain of salt), when Thunderbird asks for a password to access a mail server for the first time, it proposes to store it in order for the user to not have to enter his password each time. But this storage is not mandatory. If the user choses to enter his passord each time for security reasons, he thus may do it. I would imagine that is somewhat similar to certain distros that propose a desktop environment auto-login: that is not mandatory and the user may chose to discard this feature if he considers it a security risk Cheers :-)