When selecting a value in the JQuery UI version >= 1.9.0 the event onblur already is triggered synchronously. So call "blur()" again cause the change event trigger twice (the second trigger cause js error in wiquery-autocomplete.js).
I believe that to remove the problem it's need to delete the direct to onblur in line 137 in InnerAutocomplete subclass.
super.setSelectEvent(JsScopeUiEvent.quickScope(js.append("$(event.target).blur();")
.toString()));
The change in JQuery UI change event behavior is documented in http://jqueryui.com/upgrade-guide/1.9/#autocomplete
Thanks