Build identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1b4pre) Gecko/20090403 Mnenhy/0.7.5.20005.h2 SeaMonkey/2.0b1pre Build ID: 20090403121852, Changeset: http://hg.mozilla.org/comm-central/rev/4f871c9ec5f8 http://hg.mozilla.org/releases/mozilla-1.9.1/rev/dbb9e2e53ea6 This is the first Build were it was not possible to add another To: Cc: Bcc: or Newsgroup: Line into the Addresspane, neither Return, nor Mouse will do this Job. Todays Thunderbird-Nightly is affected too. Last known good Build ID: 20090403124907, Changeset: http://hg.mozilla.org/comm-central/rev/809750e4c971 http://hg.mozilla.org/releases/mozilla-1.9.1/rev/0c9cb75bc9ba so comm-central Checkin for Bug 194788 or mozilla-central Checkin for Bug 432068 must have caused this regression.

STR: 1. Build Thunderbird with comm-central+mozilla1.9.1 updated to -r default 2. Run Tb (in a profile that will let you compose without arguing), click the Write button on the toolbar. 3. In the "To:" textbox, type a@b.com, press return 4. Note that nothing happened, in particular that you didn't get a second "To:" added below the first, and focus didn't go to the second row of the addresswidget 5. cd mozilla && hg update -r 0c9cb75bc9ba to get back before the checkin for bug 432068, build, repeat, at step 4 note that you get a second row added and focus goes there.

I'm hoping the patch in bug 486848 will fix this; building comm-central to test that, but won't have results till tomorrow.

As per my observation, an workaround is : Use Address Book side bar to add any entry in To bar. Now you can add new entries using Enter button.

Yeah, the patch in bug 486848 fixes this.

Fixed by checkin for bug 486848.

Verified=Fixed, tested with actual Win and Linux Tinderbox-Builds. Since I am not an official QA, someone other should change the status.

This fix is rolled into the branch patches in bug 432068, adding fixed keywords here for branch verification.

Verified for 1.8.1.22 with Mozilla/5.0 (Macintosh; U; Intel Mac OS X; en-US; rv:1.8.1.22pre) Gecko/2009060204 Thunderbird/2.0.0.22pre.

Moving to Core:XUL per https://bugzilla.mozilla.org/show_bug.cgi?id=1455336