/// <summary>
        /// Release resources.
        /// </summary>
        protected override void DisposeManaged()
        {
            _provider.Added   -= AddSecurities;
            _provider.Removed -= RemoveSecurities;
            _provider.Cleared -= ClearSecurities;

            if (_ownProvider)
            {
                _provider.Dispose();
            }

            base.DisposeManaged();
        }