code: function (sId, bPrevious) {
  			this.getButtons().some(function (oButton, iIndex, aArray) {
  				if (sId === oButton.getId()) {
  					if (bPrevious) {
  						this._setFocusOnPreviousButton(aArray, iIndex);
  					} else {
  						this._setFocusOnNextButton(aArray, iIndex);
  					}
  					return true;
  				}
  			}.bind(this));
  		}
docs: Changes the focus for the Buttons in ContextMenu
  @param {string} sId the ID of the currently focused buttons
  @param {boolean} bPrevious if true, the previous button is selected instead of the next