There are 2 scenarios:
1. If an order has been back ordered, products will be displayed in the new order and the original products will be set as hidden. When importing both the original order and back order into Xero, the "hidden product" will only be in the back order, and will be hidden in the original order.
2. If you manually hide the product in the order, after importing into Xero, the hidden product will be imported into Xero and show up in the order.
We really appreciate your feedback.