Thank to Spark for this idea... I would love to have this filter also ! Would it be possible (by the way) to add the "order confirmation" type.
For most business today:
1) we send "Angebot or Offer"
2). we recieve a "PO or Bestellung"
3) we send "Order Confirmation or Auftrag Bestatigung" and finally
4) and finally, we send "Invoice or Rechnung"
Thank for your great job! Regards, Didier