WPF无法对passwordbox元素进行圆角处理

<Window x:Class="WpfApp.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="WPF PasswordBox with Rounded Corners" Height="450" Width="800">
    <Window.Resources>
        <Style x:Key="RoundedPasswordBoxStyle" TargetType="PasswordBox">
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="PasswordBox">
                        <Border Background="{TemplateBinding Background}"
                                BorderBrush="{TemplateBinding BorderBrush}"
                                BorderThickness="{TemplateBinding BorderThickness}"
                                CornerRadius="5">
                            <ScrollViewer x:Name="PART_ContentHost" />
                        </Border>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
    </Window.Resources>
    <Grid>
        <PasswordBox Style="{StaticResource RoundedPasswordBoxStyle}" Width="200" Height="30" />
    </Grid>
</Window>