find a way to make subject line in message pane take at most 4 lines, then wrap or crop. now that the fix for #91662 is in, the subject (and other headers) will take exactly one line, and will scroll instead of wrap or crop.

Your subject seems a bit misleading (or i'm just too tired). How can it "take 4 lines" and THEN wrap? Isn't it already wrapping to 4 lines? Would the following subject be more clear? "Make subject line in message pane wrap to a maximum of 4 lines, then crop remainder." This will need to be "dynamic" for when the user resized their window. Also: I haven't seen the fix for bug 91662, but if "scrolling" means the user can now no longer see the entire subject at once, then that "fix" made the situation worse than it was before, because the subject (which is almost never contiguous) previously was always readable in its entirety and was NOT the cause for bug 91662. Therefore, please fix this bug with the highest priority so we can read long subject lines without scrolling again. Needs Target Milestone and Priority. ;)

Seth, please consider bug 9942 when thinking about how to deal with this issue. There are a ton of highly relevant comments in that bug.

I came to Bugzilla this morning to look for or file a bug on the fact that subjects are now cropped. There is no way to see the entire subject if it gets cropped without using view source. Is this bug about addressing that?

If the From: line is large then the preview pane and message list panes are made large enough to show the whole From line: and the folder pane shrinks (squishes up) to be unreadable. The From: line should truncate rather than causing a resize of the preview and message list panes. The folder list pane takes up the left side from top to bottom and the message list is above the preview panes on the right side.

thunderbird equivalent is bug 413487 related SM bug which has a patch - Bug 197735 – [patch] Improve amount of visible Subject header when attachments present marking dependency as one of these might be engineered to fix the other

The patch in bug 197735 doesn't solve the actual problem.

(In reply to comment #3) > I came to Bugzilla this morning to look for or file a bug on the fact that > subjects are now cropped. There is no way to see the entire subject if it gets > cropped without using view source. Is this bug about addressing that? Yes it is; but OTOH, giving focus to the Subject line (e.g. by clicking with the mouse) allows you to scroll it (e.g. by means of the keyboard arrow keys). It isn't obvious: I didn't discover it, I had to read about it in bug 325661 comment #2 (one of the equivalent Thunderbird bugs) before I even thought of trying it. See also bug 325661 comment #4, however.

Filed bug 489609 about the same issue in Thunderbird, per request of KaiRo.

This bug is fixed in Thunderbird, see bug 489609 Fix v10.