Ok thanks VWD, that answered my question. So you need to press "Restart the entire scene" for the changes to take effect, from reading the manual I somehow got the impression that "Modify the line" was enough.

No problem, it certainly makes the trial-and-error cycle slower, but I understand that is not the slowest part of the testing cycle, simulation time is.

I look forward to spending more time with the program and trying it out.

Thanks,