When I accept or unaccept an answer, the comments get "squished" in a weird manner.
Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-US; rv:220.127.116.11) Gecko/20091201 Firefox/3.5.6
It's all coming from this question of mine.
When we added comment editing, the comment html structure changed a bit, causing some client script to behave incorrectly.
This has been fixed; thanks for submitting the bug!