As a bonus, one of my suppliers issued a credit note to cancel their first invoice. Therefore, on the invoice screen, I used More Options → Credit Note to create the credit note to cancel the invoice and entered the same date as the invoice. When I clicked on Save Details got the message: “Please enter a payment due date.” There is no box in the form to enter that “payment due date”, only credit note date.
I managed to cancel the invoice by creating a Cash Pre-payment from the supplier and then applying that to the invoice but it does not look to me as the correct solution. The point is that More Options → Credit Note on a supplier’s invoice does not seem to work?