function Leadtools.Controls.InteractiveService.startListening()
Calling this method will cause the service to hook to the EventsElement events and start firing the Tap, DoubleTap, Hold, DragStarted, DragDelta, DragCompleted, PinchStarted, PinchDelta and PinchCompleted events based on the user actions.
The ImageViewer will automatically calls StartListening on its instance of InteractiveService upon creation.