Sometimes the "Delete" icon is engaged, which makes it impossible to delete the supplier refund.
This is the case when the period in which the Refund to be reversed is located is in a closed bank reconciliation. It is not necessary for the transaction to be selected as part of the period's revenue in the bank reconciliation to prevent its cancellation. In fact, it is sufficient that the bank reconciliation for the period in question is completed and closed to prevent the transaction from being reversed.
Result:
In order to make the "Delete" icon available again and to be able to proceed with the deletion of the supplier refund, you must reopen the bank reconciliation of the period in which the refund in question is located.