Undo in Simul8
You can customize Simul8's Undo features in the Undo tab in Preferences.
It is a good idea to keep Undo enabled in case you should make a mistake that is time-consuming to recover from. However, on slow computers, or with large simulations, Undo can delay your work because of the large amount of information that the undo facility needs to handle.
If you find your simulation is slow at opening dialog boxes to edit objects on the screen, try disabling undo.
To save time Simul8's undo facility does not recover information that can be recovered by running the simulation. So the simulation clock is normally reset to zero while you UNDO.
You can ask Simul8 to be able to undo all the results and running information too by unchecking the ALWAYS RESET THE CLOCK AFTER UNDO check box.