Labels (callouts) at both ends of a relationship as well as in the middle

It would be very useful to have callouts on a relationship at both ends as well as in the middle.

• This would enable the connections in a Causal Loop Diagram to be annotated at the remote node with "+" or "-".
• It would allow information about the other end of a relationship to be made visible at the local end. Currently both ends may need to be in view to properly assess a relationship. This can be problematic in large maps.
• It would enable forward and backward links to be handled differently on export or analysis.