User-agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-US; rv:1.9.2.4) Gecko/20100608 Thunderbird/3.1
Miles,
I've (hopefully) fixed your problem, just try revision 533. Do you need
a real tag or is the revision number sufficient? Let me know if 533
works, that I can tag that version for you.