User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; de; rv:1.9) Gecko/2008052906 Firefox/3.0 Build Identifier: Version 2.0.0.14 (20080421) I sent an e-mail to one(!) address (mal)formed like this: ab., cd., ef., 2x gh. <bla@moo.invalid> After sending the e-mail, it turned out that because of the commas, Thunderbird did read the address like this: ab., cd., ef., "2x gh." <bla@moo.invalid> and it sent the e-mail to four recipients instead of one. I did then receive this error message from the mail server: |------------------------- Failed addresses follow: ---------------------| <ab.> You must specify a domain name. <cd.> You must specify a domain name. <ef.> You must specify a domain name. This could have been prevented if Thunderbird would warn about malformed e-mail addresses, in this case I should have put quotes around the display name, like this: "ab., cd., ef., 2x gh." <bla@moo.invalid> But it was too late, since Thunderbird did send the email without warning. :/ Reproducible: Always Steps to Reproduce: 1. Write an e-mail with a malformed e-mail address as recipient (see details above). 2. Press "Send". 3. Expect to get an error message from the mail server, but no warning from Thunderbird. Actual Results: The e-mail is sent instantly. Expected Results: Thunderbird should warn that some of the "four" e-mail addresses (intented as one address, not four) are malformed. A similar issue is described at bug 345995 (https://bugzilla.mozilla.org/show_bug.cgi?id=345995).

I just noticed that when you use the tab key instead of clicking elsewhere, the email address is deleted, so it looks like there *is* a check already built-in, however it is only performed when pressing tab.

Well it's true, there is a different behaviour: if you click TAB after having written a comma-separed address, the (wrong) addresses will be erased, if you click elsewhere, they will remain, letting you send mails and receive the server error message

(In reply to comment #1) this seams so much like bug 356032

(In reply to comment #2) > Well it's true, there is a different behaviour: if you click TAB after having > written a comma-separed address, the (wrong) addresses will be erased, if you > click elsewhere, they will remain, letting you send mails and receive the > server error message Tab key does auto complete the addresses, and there the the addresses disappear due bug 348825. (In reply to comment #3) > (In reply to comment #1) > this seams so much like bug 356032 This is not a duplicate of bug 356032, relates to it just because if you would have a address like "ab., cd., ef., 2x gh." <bla@moo.invalid> after auto complete (TAB), the result will be invalid. Also, for me this doesn't seem like a bug, as Thunderbird has no place in validating email addresses, there are cases where ab., cd., ef., are actually 3 valid emails hth