code: function($item, preventScroll) {
              if (preventScroll) {
                  var scrollLeft = Garnish.$doc.scrollLeft(),
                      scrollTop = Garnish.$doc.scrollTop();
                  $item.focus();
                  window.scrollTo(scrollLeft, scrollTop);
              }
              else {
                  $item.focus();
              }
  
              this.$focusedItem = $item;
              this.trigger('focusItem', {item: $item});
          }
docs: Sets the focus on an item.