Simulation doesn't end properly

[DongweiYe]

The experiments with ISR3D works fine but doesn't end properly. The submodels will just hanging there and don't know that the simulation has already finished. Same thing happens to MUSCLE3 manage. It seems the managar doesn't know when to kill the simulation as well.

[LourensVeen]

It seems like the problem here was that the model had its ports assigned to operators incorrectly. A bigger problem is that MUSCLE3 will not check that, and then hang on shutdown because it's trying to send messages on ports it's supposed to be receiving on.

• [ ] Check on send that the port has an appropriate operator
• [ ] Check on receive that the port has an appropriate operator
• [ ] Add a simple rule to the documentation for deciding which operator a port belongs to
• [ ] Have the error message generated above refer to that documentation (or reiterate it)