The simulation 'random' for 'symbolic simulator' and 'concrete simulator' is not stopped when I try to load another model.
I think the concrete one is being stopped when the tab is deselected, but not the symbolic one. This non-stopping could be a feature when the user wants a random trace but does not want the window redrawing overhead.
Also it would be nice to have "turbo" mode for the fastest random simulation, where the GUI is redrawn only once per second or so, because right now it is forcing repainting every single time it changes, and thus unnecessary incurs significant overhead.
Anyway I leave it to you, Wei.