code: function () {
              this.clearPlaceholder(); // should be done before super so placeholder is not used to search
              this.resizeSearch();
  
              this.parent.opening.apply(this, arguments);
  
              this.focusSearch();
  
              this.updateResults(true);
              this.search.focus();
              this.opts.element.trigger($.Event("select2-open"));
          }
docs: multi