code: function () {
  
              var aButtons = this.cfg.getProperty("buttons"),
                  oButton,
                  oElement;
  
              if (aButtons && Lang.isArray(aButtons)) {
                  oButton = aButtons[0];
                  if (oButton) {
                      oElement = this._getButton(oButton.htmlButton);
                      if (oElement) {
                          /*
                              Place the call to the "focus" method inside a 
                              try/catch block to prevent IE from throwing 
                              JavaScript errors if the element is disabled 
                              or hidden.
                          */
                          try {
                              oElement.focus();
                          } catch(oException) {
                              // ignore
                          }
                      }
                  }
              }
          }
docs: Sets the focus to the first button created via the "buttons"
  configuration property.
  @method focusFirstButton