public virtual void CustomScrollWheel(int rotationDelta)
        {
            //if (rotationDelta >= 120 || rotationDelta <= -120)
            //{
                if (VScrollBarVisible)
                {
                    Point current = CustomScrollPosition;
                    int newY = current.Y +
                        SystemInformation.MouseWheelScrollLines * VScrollBar.SmallChange * -Math.Sign(rotationDelta);

                    //check that the value is between max and min
                    if (newY < 0)
                        newY = 0;
                    if (newY > MaximumVScroll)
                        newY = MaximumVScroll;

                    CustomScrollPosition = new Point(current.X, newY);
                }
            //}
        }