If you have items in your menu that are not showing in your Library list then at some point a menu was copied from one Location to another. You can see ALL items by un-selecting to Show Item Items for this Location Only.
Login to OrderCloud
Select Manage Stores
Select the Location
Select the Admin tab
Under the Menu Management section, select the button Show Items for this Location only to de-activate.
All items will appear on the Item Library list.