When entering a Purchase Order manually it can be difficult to know which Items should be purchased from the selected vendor. A Line function similar to the "Select Items" function, but that shows a filtered list of items where the vendor on the purchase order is the default primary vendor or a secondary vendor for an item. This would aid in creating purchase orders for a vendor without going through the whole item list, especially as you can only filter the normal Item list by the Vendor where it is the primary for an item.