private void OnHandleDestroyed(object sender, EventArgs e)
 {
     if (_filterInstalled)
     {
         Application.RemoveMessageFilter(_filter);
         _filterInstalled = false;
         _filter          = null;
     }
 }
        private void OnContainsFocus()
        {
            if (!_filterInstalled)
            {
                if (_filter == null)
                {
                    _filter = new ComponentContainerScrollMessageFiler(this);
                }

                Application.AddMessageFilter(_filter);
                _filterInstalled = true;
            }
        }