code: function () {
              var element=this.opts.element, select2 = element.data("select2");
  
              if (this.propertyObserver) { delete this.propertyObserver; this.propertyObserver = null; }
  
              if (select2 !== undefined) {
                  select2.container.remove();
                  select2.dropdown.remove();
                  element
                      .removeClass("select2-offscreen")
                      .removeData("select2")
                      .off(".select2")
                      .prop("autofocus", this.autofocus || false);
                  if (this.elementTabIndex) {
                      element.attr({tabindex: this.elementTabIndex});
                  } else {
                      element.removeAttr("tabindex");
                  }
                  element.show();
              }
          }
docs: abstract