Stop assking for passphrase

hi there, looking for some help.
has a email acc and started o use it with thunderbird. installed pgp4win and enigmail.
now everytime ,like every few minutes i get asked for a passphrase to unlock the secret key. sick and tired having to enter it everytime,iv tried many options like:
“never ask for a passphrase” option in enigmail
“remmeber passphrase for 9999 minutes of idle time”
"use pgp-agent for passphrase " under advanced
but none of them work i still get asked for the damn passphrase every few minutes or when sending a mail. is there a way to disable this?please help if anyone know the answer .thanks in advance