code: function(e) {
          var E = YAHOO.util.Event,
              KEYS = YAHOO.util.KeyListener.KEY;
  
          if (E.getCharCode(e) == KEYS.TAB && !e.shiftKey) {
              try {
                  E.preventDefault(e);
                  this.firstCtrl.focus();
              } catch (err) {
                  // Ignore - mainly for focus edge cases
              }
          }
      }
docs: Default Keyboard event handler to capture Tab
  on the last control (lastCtrl) in the Navigator.
  
  @method _handleTabKey
  @protected
  @param {Event} e The DOM event being handled