User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.0.1) Gecko/2008072820 Firefox/3.0.1 Build Identifier: The automatically inserted linebreaks stay attached to whatever word they were before/after, so that when editing a draft message, inserted words can end up on lines of their own. Reproducible: Always Steps to Reproduce: 1. Create a new message and type in some 100 characters (no line breaks). 2. Save the message. 3. Open the message for editing from the Drafts folder and append a new word at the end of the first line. Actual Results: The paragraph is not wrapped correctly; the appended word is on a line by itself despite not being the last word of the paragraph. Expected Results: The appended word should not be on a line by itself since it is not the last word in the paragraph. Instead, linebreaks are recalculated to account for the new word. Reported in Launchpad here: https://bugs.edge.launchpad.net/ubuntu/+source/thunderbird/+bug/120281 by August Karlstrom