WPF Popup: How to put a border around the popup?

Much easier in my opinion is putting a margin around the Popup Border large enough for the DropShadowEffect, i.e.

<Border ... Margin="0 0 8 8">    <Border.Effect>        <DropShadowEffect ... />    </Border.Effect>    <!-- Popup Content Here --></Border>

The Popup should allow transparency, that is AllowsTransparency = True.

<Popup PopupAttributes="SetByYou"> <Border BorderAttribute="SetByYou">  <!-- Content here --> </Border></Popup>

Apparently popups don't currently support drop shadows, see link.

However, I have come up with a workaround this which works rather well IMO. Basically the idea is to have a Canvas nested within another transparent Canvas and just apply the drop shadow to the nested Canvas. Simple. Heres an example:

        <Grid>        <TextBox x:Name="MyTxtBx" Width="50"                  Height="20" Text="Hello"/>        <Popup IsOpen="True" Width="200" Height="100"                PlacementTarget="{Binding ElementName=MyTxtBx}"                AllowsTransparency="True" >            <Canvas Background="Transparent">                <Canvas Background="Green" Width="150" Height="50">                    <Canvas.BitmapEffect>                        <DropShadowBitmapEffect Softness=".5"                                                 ShadowDepth="5"                                                 Color="Black"/>                    </Canvas.BitmapEffect>                    <Label Content="THIS IS A POPUP TEST"/>                </Canvas>            </Canvas>        </Popup>    </Grid>

The points to note are that the nested canvas needs to be smaller than the size of it's container. Also AllowsTransparency must be set too.