This feature is available in Evergreen version 2.3.
In previous versions, by default, a purchase order could be activated with or without copies attached to line items.
In version 2.3, by default, a purchase order cannot be activated if a line item on the purchase order has zero copies. A new feature enables you to activate a purchase order that lacks copies.
To activate a purchase order with line items that have zero copies, check the box Allow activation with zero-copy lineitems.
Author: Sally Fortin, Equinox Software