WPF shadow on stackpanel controls

Answer 1

You can do use Panel.ZIndex="0" in each of the Borders to set the z order of the items directly from the XAML.

<StackPanel>
    <Border Height="100" Width="100" Background="Red" Panel.ZIndex="1">
        <Border.BitmapEffect>
            <DropShadowBitmapEffect Color="Black" Direction="270" ShadowDepth="3" Opacity="1" Softness="2" />
        </Border.BitmapEffect>
    </Border>
    <Border Height="100" Width="100" Background="blue" Panel.ZIndex="0">
    </Border>
</StackPanel>

Or you can use StackPanel.SetZIndex(object, value) if you wanted to do it from code.