I’m wondering whether you guys support a use-case of having a diagram (as a node) inside of another diagram. If there is a sample, that would be great. I’m not sure how your events work at this point.
How about the possibility of having a node from Diagram A to link to another node in Diagram B?
A long time ago we tested having a Diagram inside a Node’s DataTemplate. I think that should work fine.
As far as linking between Diagrams, that could work if both Diagrams are inside a containing Diagram. Some extra work would be needed for:
handling multiple models, one for each diagram, and deciding how to implement cross-model references
dealing with the ambiguity of a link being connected to a node containing a diagram as well as to a particular node/port inside that diagram
scrolling or zooming in either nested diagram would require calling Node.InvalidateRelationships() so that all of the links connected to the node could be re-routed appropriately
handling links that connect to nested nodes that are scrolled off the nested viewport
dealing with copying (and deleting?) nodes
However, before you proceed with that course of action, I would investigate whether alternatives would work better and also be easier to use. What’s wrong with using Groups instead of nested Diagrams? The user wouldn’t be able to scroll/zoom the subgraphs, but it’s all a lot easier to manage, in a single model.