Intermediate Link events (catch/throw) are typically used in place of long sequence flows that span the length of diagrams. They aren't really "events" in that nothing is really happening. We should therefore prevent users mapping events to them. This should definitely be done in the frontend, and possibly with some validation in the backend too.

ATs:

• User can not map events to link throw intermediate catch events or link intermediate throw events
• We consider adding this constaint in our Event-Based process documentation