Pre payment check doesn't seem to work with drop shipments

QR_Nicole

The check on pre payment before posting doesn't seem te work on drop shipments:

I have created a sales order and connected a purchase order through drop shipment.
The sales order needs to be pre paid, so I created a pre payment invoice, yet to be paid.
Then the purchase order is posted as received.
Because of the drop shipment connection, at the same time the sales order is posted as shipped.
However, I expected the sales order would not post because of the pre payment check...

What am I doing wrong?
Or don't the two functionalities (drop shipment and pre payment) work together?