gistfile1.txt

listen(this.view.getElement(), ['mousedown', 'touchstart'], function(e) {
        var v = this.listenVertex_.get(goog.getUid(e.target));
        if (v) {
            dispatchEvent(this, new SelectionEvent(this, e, v));
        } else {
            var edge = this.listenEdge_.get(goog.getUid(e.target));
            if (edge) {
                dispatchEvent(this, new SelectionEvent(this, e, edge));
            }
        }
    }.bind(this));