code: function (panel) {
                  var self = this, bar = self.get('bar'), body = self.get('body'), selectedPanelIndex = util.indexOf(panel, body.get('children'));
                  body.set('selectedPanelIndex', selectedPanelIndex);
                  bar.set('selectedTab', self.getTabAt(selectedPanelIndex));
                  return this;
              }
docs: set panel as selected
  @param {KISSY.Tabs.Panel} panel
  @chainable