When the balance open for a purchase order line is zero, the line is closed. When all lines are closed, the purchase order is closed. However, it is possible to receive more than the ordered quantity into dock receiving. If only the amount on the PO is received, the extra quantity remains left in Dock Receiving, then it will display as open to be received, but as closed status when selecting an order for PO Receiving.  This can be cleared by reversing the dock receipt, or completing the receipt in PO Receiving.

Please refer to the Purchase Order Receiving Management module.