/// <summary>
 /// Handles when the closest point to the mouse cursor changes. Hides
 /// or shows the closest point, and changes the mouse cursor accordingly.
 /// </summary>
 /// <param name="sender"></param>
 /// <param name="e"></param>
 void closestPointPicker_ClosestPointChanged(object sender, ClosestPointArgs e) {
   Locked = _closestPointPicker.Locked;
   LockPoint = _closestPointPicker.ClosestPoint;
 }
 /// <summary>
 /// Handles when the closest point to the mouse cursor changes. Hides
 /// or shows the closest point, and changes the mouse cursor accordingly.
 /// </summary>
 /// <param name="sender"></param>
 /// <param name="e"></param>
 void closestPointPicker_ClosestPointChanged(object sender, ClosestPointArgs e)
 {
     Locked    = _closestPointPicker.Locked;
     LockPoint = _closestPointPicker.ClosestPoint;
 }