WPF ModelVisual3D Viewport2DVisual3D

<Window x:Class="WpfApp110.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WpfApp110"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <Grid>
        <Viewport3D>
            <Viewport3D.Camera>
                <PerspectiveCamera
                    Position="0.2,0.1,1"
                    LookDirection="-0.2,-0.1,-1"
                    FieldOfView="120"/>
            </Viewport3D.Camera>
            <Viewport3D.Children>
                <ModelVisual3D>
                    <ModelVisual3D.Content>
                        <DirectionalLight Direction="-0.3,-0.4,-0.5"/>
                    </ModelVisual3D.Content>
                </ModelVisual3D>
                <Viewport2DVisual3D>
                    <Viewport2DVisual3D.Geometry>
                        <MeshGeometry3D Positions="-1,1,0 -1,-1,0 1,-1,0 1,1,0"
                                        TextureCoordinates="0,0 0,1 1,1 1,0"
                                        TriangleIndices="0 1 2 0 2 3"/>
                    </Viewport2DVisual3D.Geometry>
                    <Viewport2DVisual3D.Material>
                        <DiffuseMaterial Viewport2DVisual3D.IsVisualHostMaterial="True"/>
                    </Viewport2DVisual3D.Material>
                    <Button>Hello,3D</Button>
                </Viewport2DVisual3D>
            </Viewport3D.Children>
        </Viewport3D>
    </Grid>
</Window>