The scripts attached to these buttons demonstrate how to return to a specific frame, rather than the beginning of the movie, when the projector is restarted.
The right button calls "savePosition" which records the position to return to
(in this case, the label "ReturnMenu") before calling zLaunch.
The startMovie handler calls "restorePosition" when the projector restarts,
and returns the user to the saved location, if any.