GnuPG on Mac OS

[Anthony Papillion]

So I've installed GnuPG on a friends Mac and, for the most part, it's
working fine. She can encrypt/decrypt/sign with no problems at all. But,
for some reason, every time she does one of those functions, she has to
re-enter her passphrase. She's using the Enigmail plugin for Thunderbird
and we set the 'remember passphrase for' option to 500 minutes but it's
ignoring it.

Am I missing something crucial here? How can I get it to remember her
password for a longer period. I know this sounds like an Enigmail
question but I'm asking here because I think it has to do with GPG-Agent
or some other component of the tools.

Can anyone help?

Thanks1
Anthony