It may be stuck occasionally and after a few seconds of inactivity this may occur. It's similar in all browsers, without addons. It may depend on the thread, e.g. I believe I saw it on an old thread (2 days old). - - - Updated - - - e.g. I saw it in this thread right now http://www.mmo-champion.com/threads/...-AOE-fire-mage - - - Updated - - - Aha! I found a workaround. If the quotation is removed entirely, it works! Then if I edit-in the quotation it saves it. Very peculiar.