@PD, why do you want to start an optimization on an event like On Model Open. I don’t think it would appropriate to do this action in any other scenario, because those scenarios involve a reset of a model and then you can start an optimization by statistic menu, too.
Edit: you won’t find a result in a tree, because your model gets executed in several instances parallel on your CPU. A model run in FlexSim is a single thread in a CPU core.
There doesn’t exist a single main master process during an optimization in OptQuest, which you can manipulate by methods of FlexSim. An Optimization is an external process only started from within FlexSim. FlexSim provides only an interface to this external tool.