That pretty much defeats the purpose of the VI. The whole point of the exercise was to figure out how big to size the VI relative to the monitor so the caller VI could maximally lay out its controls without taking up the whole screen... and if I don't know which monitor it is on, it doesn't work. 🙂 BUT... you made a great point about the run-time engine.  You're right that I should have avoided the use of scripting, esp since there's a dead obvious existing VI to use -- the subVI itsel