code: function() {
  			var sOverflowButtonId = "OVERFLOW_BUTTON",
  				oButtonOptions = {
  					icon: "sap-icon://overflow",
  					type: "Transparent",
  					enabled: true,
  					press: this._onOverflowPress.bind(this),
  					layoutData: new FlexItemData({})
  				};
  			return this._addButton(sOverflowButtonId, oButtonOptions);
  		}
docs: Adds a overflowButton to the ContextMenu.
  @return {sap.m.ContextMenu} Reference to this in order to allow method chaining
  @public