User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2a1pre) Gecko/20081215 Firefox/3.2a1pre Build Identifier: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1b3pre) Gecko/20081216 Thunderbird/3.0b2pre If an email has a lot of entries in "to" or "cc" field, the clickable "more" indicator allows to unwrap the headerValueBox to display all the entries. If the message header pane is set to display details, the "more" indicator remains visible and clickable after the headerValueBox has been unwrapped. Clicking the "more" indicator again makes it disappear, leaving no direct and obvious way to wrap headerValueBox again except of selecting another message. Please ignore this bug report / mark it invalid if a fix for the Bug 456596 would turn this one obsolete. Reproducible: Always Steps to Reproduce: 1. Make the Thunderbird window wide enough or maximize it 2. Select an email with many entries in the "to" or "cc" field 3. If the message header pane was not set to show details yet, do it now 4. Click on "more". Actual Results: The "more" indicator has moved next to the "reply" button. Clicking it again will just make it collapse and disappear, leaving an unexperienced user without an easy option to fold the unwrapped field again. Expected Results: "more" is at least not shown anymore after Step 4 or, better, it turns into "less" to be able to wrap the headerValueBox again. This behavior has been possibly introduced by checkins in Bug 456818.

The unwrapped "to" field below compared to the "to" field wrapped: "more" is still displayed.

Hope that this testcase will make it easier to reproduce the issue and to prevent the bug from making it into a post-b2 release, if no total overhaul of the new message header pane is planned anyway.

I see this too. Quite ugly.

Current theory is to investigate doing the more & wrapping using a more XBL/DOM-centric strategy; the current implementation mostly uses CSS. davida suggests that the patch in bug 436555 has a trick for using CSS from JS to detect overflow that may be helpful.

Patch is in progress, but, unfortunately, I got sucked into a security firedrill this past week. Pushing out to [m3].

What's actually going on here is slightly different than what's described in comment 0: when the (more) on the To line is clicked and unfolded, it disappears. A different (more) shows up on the From line at that point. The patch discussed thus far (that I think will probably fix this) actually belongs in bug 499989; I'll post it there shortly.

As far as I can tell (by using the test case provided here, which was very handy; thanks!), the <grid>ification patch in bug 469878 has made this problem go away. The nightlies built tomorrow (Thursday, September 10) will contain this fix. Resolving as FIXED; if you see this bug again in builds from September 10th or later, feel free to reopen.