Just a comment: It took me hours to figure out that acts_as_list is the culprit of an erratic behaviour in my model (I am still a newb). My model changes some other model before_save. Upon destroy, those changes seem to be reversed by acts_as_list. I applied this patch: http://railsforum.com/viewtopic.php?id=20558 . The problem is solved. I just don't know why the patch has not been applied to http://github.com/rails/acts_as_list .