By default, when an invoice (or its line items) is deleted, the dispatch note generated from that invoice is also deleted.
If the value false is entered in the zdrojProSkl (Source for warehouse documents) field when creating an invoice, the dispatch note created from that invoice will not be deleted when the invoice (or its line items) is removed.
If the value true (the default value) is entered, the dispatch note will automatically be deleted along with the removal of the invoice (or its line items).