Small Wine Barrels must be completed on the ground. If you have more than 16 on a single tile you can not add them to crafting window, at 17 of them, they turn into a flat graphic of started items. You can not add them to crafting window and can only continue by manually ( or using a hot key, select component ) Continue Building option. - don't see any reason why they can't be added to crafting window if you can continue building them manually -