protected virtual void Mouse_WheelChanged(object sender, OpenTK.Input.MouseWheelEventArgs e)
 {
     if (FocusedElement != null)
     {
         FocusedElement.MouseWheel(e);
     }
 }
        protected virtual void Mouse_WheelChanged(object sender, OpenTK.Input.MouseWheelEventArgs e)
        {
            if (FocusedElement != null && FocusedElement.ReceiveMouseWheel)
            {
                FocusedElement.MouseWheel(e);
            }

            if (Receiver != null && ShouldNotifyReceiver())
            {
                Receiver.MouseWheel(e);
            }
        }