when receiving a mail with a to-line like this: To: =?iso-8859-1?Q?Fa=2E_St=FCrtz=2C_Engel?= <c.engel@stuertz.de> Mozilla 1.7.3 does something like that out of it: "Fa. Stürtz", "Engel <c.engel@stuertz.de>" so you got 2 addresses out of one! the correct interpretation would be: "Fa. Stürtz, Engel <c.engel@stuertz.de>" (only one address) Best regards, Christof Engel, chris@engelc.de

Problem was re-created with Mozilla Suite latest-trunk 2004121305(Win-2K). Re-creation procedure. (1) Create a draft mail (Compose a mail and save in Drafts) (2) Terminate Mozilla(both browser & mailnews) (3) Edit "Drafts" file by text editer, change To: header to To: =?iso-8859-1?Q?Fa=2E_St=FCrtz=2C_Engel?= <c.engel@stuertz.de> and save file (4) Delete "Drafts.msf" (5) Retart Mozilla (6) See the draft mail, then "Edit Draft" => To: is splitted to two recepients This problem did not occur when "\"(=5C,escape char) is inserted before ","(=2C), To: =?iso-8859-1?Q?Fa=2E_St=FCrtz=5C=2C_Engel?= <c.engel@stuertz.de> although another problem occurs. - Display becomes Fa. Stürtz\\, Engel Special data was displayed(escape char in this case). This is already reported problem. (Sorry but I'm not familiar with Quoted Printable. ) (So I don't know whether result of inserting "=5C" only is valid QP or not.) I can not say RFC 2822 says which, "," in atom should be escaped, or no need of escaping.

Bug 274603 is bug for same problem on From: header, and has been closed as DUP of Bug 254519. Bug 254519 have many DUP bugs, and Bug 191102, one of the DUP bugs of it, is "To:" header case and same problem as yours. Close this bug as DUP of Bug 254519. *** This bug has been marked as a duplicate of 254519 ***