See the conversation titled ''possible bug in event code'' in dev list.

In event.js line 46

var handle = jQuery.data(element, "handle", function(){

should instead be

var handle = jQuery.data(element, "handle") || jQuery.data(element, "handle", function () {

David: "It looks like the code was always creating a new handle for each event

added instead of getting an existing handle out of the cache when it

was already there."

The handlers overwritten can never be removed and cause memory leaks.

Related tickets are #1697, #1618 and #1610.