User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.13) Gecko/20080311 Firefox/2.0.0.13 Build Identifier: version 2.0.0.12 (20080213) I am receiving emails from China with From: and CC: addresses starting with the names stored in Big5 base64-encoded. If I View Message Source, I see lines like this: =?big5?B?[rest of the name is encoded here]?= <name@domain.com>, When decoded, the part in the name area contains "lastname, firstname". This is interpreted by Thunderbird as two separate addresses: lastname firstname <name@domain.com> This shows up as two addresses in the From: field, for instance, and when I press Reply, each of these "addresses" is shown on a separate line in the To: area, giving me invalid email address errors for the lastnames when I try to send. Reproducible: Always Expected Results: Commas inside email names should be treated as part of the name, not as an inter-address separator, no matter what the encoding.