By default, the OnMouseWheel property is exMouseWheelZoom | exMouseWheelScroll, which indicates that rolling the mouse button, may scroll or zoom the face from the cursor. If the face displays a scrollable control, the scroll is performed, else the zoom is performed. The OnMouseWheel property specifies what action the control performs when user rolls the mouse wheel. Use the OnMouseWheel  property to disable / enable scroll / zoom of the face from the cursor. The FaceFromPoint property returns the index of the face from the cursor.