This functionality is new as of version 4.1.
To Save a Purchase Order Delivery:
After creating the Purchase Order Delivery.
Click the ‘Save’ button.
Before the Delivery is Completed, this will save the editable fields and the new Delivery Items.
If the ‘Received Qty’ is 0 (zero), the Delivery Item will be removed from the list when it is saved.
When the Delivery is resumed, the Delivery Items can be added individually, or by clicking the ‘Add All Items’ button. Delivery Items that are already in the list will be ignored.
To complete the Delivery, it must be ‘Completed’.