code: function (aNavigableItems) {
  				// Initialize the ItemNavigation if required
  				if (!this.oItemNavigation) {
  					this.oItemNavigation = new ItemNavigation();
  					this.addDelegate(this.oItemNavigation);
  				}
  
  				this.oItemNavigation.setRootDomRef(ToolbarRenderer.getPopupArea(this.oToolbar));
  				this.oItemNavigation.setItemDomRefs(aNavigableItems);
  				this.oItemNavigation.focusItem(0);
  			}
docs: Initializes the ItemNavigation for this popup and focuses the first item
  
  @param aNavigableItems The DOM references of the toolbar items displayed in this popup
  @private