i think it is. The related entity only sets a filter for the parent entity. the behavior that you describe can be achieved when having a Composition (like from Order --> LineItems). Within the normal edit screen of the order, you will be able to see only the lineItems of the order, and when you add a new line item - the order will be set for the line item.
It is an interesting question to think about for a possible extension of the related entity feature.
Basically it would mean, that when a certain related entity screen is opened, you basically set the context to only act on a particular subpart of the data:
- see only the items (lineItems) that are related to the original one (order)
- When doing the normal CRUD stuff, it will use the context as well for setting the order
- It could potentially be a little more prominent in the UI in which context the user acts (like the selected order etc), because right now it’s not even displayed in the generic filter component (at least not very prominently)
Perhaps the CUBA folks have some opinions on these ideas?