Hello Gigha,
thank you for your answer, I understand and you have done everything correctly.
But to implement the functionality that you want, we need to do it a little differently...
For the list form of the document "InvoiceExchange", we should switch the DynamicList "List" to use custom queries. We will pass a list of already added documents to this query, and they will not be shown then.
Do you know how to do this?