User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.7.5) Gecko/20041107 Firefox/1.0 Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.7.5) Gecko/20041107 Firefox/1.0 I am regularly encountering a bug in replying to EMails sent via MS Exchange. Here in Germany, people tend to have Umlauts in their name. In this case, Exchange encodes the realname part of the "from" line. prefixing it with "=?iso-8859-1?Q?" - but WITHOUT enclosing the realname part in quotes. This is OK per the RFC, since entities enclosed in this way should be treated as atoms, even if they are not enclosed in quotes. Thunderbird, unfortunately, does not handle this correctly. Say I receive an EMail fomr someone who has configured his realname to be - for whatever reason - "Bill Müller, Darmstadt, SU2-DA55" (people have this, e.g. when a full name and position description are plucked from a company X.500 directory). Since "Müller" contains an Umlaut, Exchange decides it needs to encode the "from" entry. So it sends a from line something like this: =?iso-8859-1?Q?Bill M=FCller=2C_Darmstadt=2C_SU2-DA55?= <bill@somewhere.else> Thunderbird now decodes this wrongly, not realising that the WHOLE thing enclosed in =?iso-8859-1?Q? and ?= is the realname, and splits it into multiple recipients. It treats the comma as an address delimiter, rather than as part of the atom making up the sender's name. This means that when I hit reply, I end up replying to multiple recipients: Bill Müller@mydomain.com Darmstadt@mydomain.com SU2-DA55@mydomain.com bill@somewhere.else Each time I have to go to the recipient list and remove the extra entries. Reproducible: Always Steps to Reproduce: Ger mail from some with Umlaut in name and using Exchange mail server. Reply. :-)

Looks like a duplicate of Bug 254519.

Yes, it really *is* a duplicate. Seems I didn't seach thouroughly enough. *** This bug has been marked as a duplicate of 254519 ***