As Tristan discovered, repetitive invocation of "Run as NDDL model" produces multiple entries in the Debug perspective with no way to do anything about those entries. In fact, only one copy of the solver model exists at any given moment.

Need to figure out how to connect to those stale configurations in the Debug perspective and either clean them up when a new model is started or at least show them as terminated.

In the future need to support multiple parallel sessions, but this is a longer story and another ticket.

Fixed in revision 6271.