Change PO status to Green after the PO is marked sent NOT when saved

The status of the item and PO in the Overview screen is checked green when the PO is saved.
I want the status to change to a green check mark only when the PO is marked sent.

We work with many vendors that do not have a live connection with Deco so my purchasing likes to save the PO, print it out, and then process the order with the supplier. Sometimes they forget to place the order and at the time of production, the goods are missing which causes delayed shipments or loss of sales. Because of the green checkmark, it bypasses the production radar since they are under the assumption that the goods have been ordered.