code: function(text, innerNodeType) {
  			var li = createMenuItem(text, innerNodeType);
  			this._dropdownNode.appendChild(li);
  			return li;
  		}
docs: Creates a new menu item and appends it to the bottom of this dropdown.
  @param {String} text The text to display inside the new menu item. Optional.
  @param {String} innerNodeType The type of the inner node to create. The default is "span". Optional.
  @returns {Object} The top-most new element that was created