if (event.getType() == ListDataEvent.STRUCTURE_CHANGED && _model instanceof Sortable && _listhead != null) { //ZK-1705 added null check for _listhead
                Sortable<Object> smodel = cast(_model);
                List<Listheader> headers = cast(_listhead.getChildren());
                boolean found = false;
                for (Listheader col : headers) {