/// <inheritdoc />
        public void NotifyBlockRemoved(BlockRemovedEventArgs args)
        {
            var view = (FrameworkElement)args.BlockRemoved.Tag;

            Debug.Assert(Children.Contains(view));
            Children.Remove(view);
        }
        /// <inheritdoc />
        public void NotifyBlockRemoved(BlockRemovedEventArgs args)
        {
            var view = (FrameworkElement)((IDocumentItem)args.BlockRemoved).Tag;

            _childContents.Children.Remove(view);
        }