Purchase Ledger - Invoice Entry - Pop-up to display URN Required on saving Merged

When posting a purchase ledger invoice (either via Purchase ordersrecord invoice or SuppliersEnter Transactions) we have been shown during training that we have to go into the individual supplier account after entering every single purchase ledger invoice and look-up the invoice we have just entered to retrieve the transaction URN (as we want to note the URN on each posted invoice and file it using this reference). The sales ledger/ nominal journals both have a pop-up following save that shows a unique reference number but the purchase ledger does not. IDEA: Pop-up displaying URN on saving purchase ledger invoice.