protected override void OnRender(System.Windows.Media.DrawingContext drawingContext)
    {
        base.OnRender(drawingContext);
        var                root               = Window.GetWindow(this);
        var                adornerLayer       = AdornerLayer.GetAdornerLayer(AdornedElement);
        var                presentationSource = PresentationSource.FromVisual(adornerLayer);
        Matrix             transformToDevice  = presentationSource.CompositionTarget.TransformToDevice;
        var                sizeInPixels       = transformToDevice.Transform((Vector)adornerLayer.RenderSize);
        RenderTargetBitmap rtb           = new RenderTargetBitmap((int)(sizeInPixels.X), (int)(sizeInPixels.Y), 96, 96, PixelFormats.Default);
        var                oldEffect     = root.Effect;
        var                oldVisibility = AdornedElement.Visibility;

        root.Effect = new BlurEffect();
        AdornedElement.SetCurrentValue(FrameworkElement.VisibilityProperty, Visibility.Hidden);
        rtb.Render(root);
        AdornedElement.SetCurrentValue(FrameworkElement.VisibilityProperty, oldVisibility);
        root.Effect = oldEffect;
        drawingContext.DrawImage(rtb, adornerLayer.TransformToVisual(AdornedElement).TransformBounds(new Rect(adornerLayer.RenderSize)));
        drawingContext.DrawRectangle(new SolidColorBrush(Color.FromArgb(22, 0, 0, 0)), null, adornerLayer.TransformToVisual(AdornedElement).TransformBounds(new Rect(adornerLayer.RenderSize)));
        drawingContext.DrawRectangle(new VisualBrush(AdornedElement)
        {
            AlignmentX = AlignmentX.Left, TileMode = TileMode.None, Stretch = Stretch.None
        },
                                     null,
                                     AdornedElement.RenderTransform.TransformBounds(new Rect(AdornedElement.RenderSize)));
    }