Draggable breaks in IE7 IE8

When i refresh a Tree on IE7/8 the dragged object never call the "stop" event and the clone object is leaved everywhere on the screen...

Adding "if( $(this).data('draggable') )" on this stop event solved this problem for me...

$.ui.plugin.add("draggable", "cursor", {

start: function(event, ui) {

var t = $('body'), o = $(this).data('draggable').options;

if (t.css("cursor")) o._cursor = t.css("cursor");

t.css("cursor", o.cursor);

},

stop: function(event, ui) {

if( $(this).data('draggable') )

{

var o = $(this).data('draggable').options;

if (o._cursor) $('body').css("cursor", o._cursor);

}

}

});