[C#/WPF] BlockUIContainer 엘리먼트 사용하기

<FlowDocumentScrollViewer>
    <FlowDocument>
        <Paragraph>"Be who you are and say what you feel, because those who mind don't matter, and those who matter don't mind. - Dr. Seuss</Paragraph>
        <BlockUIContainer>
            <StackPanel
                HorizontalAlignment="Center"
                Orientation="Horizontal">
                <Button
                    Margin="10"
                    Width="100"
                    Height="30"
                    Content="Like it" />
                <Button
                    Margin="10"
                    Width="100"
                    Height="30"
                    Content="Don't like it" />
            </StackPanel>
        </BlockUIContainer>
        <Paragraph>We continue this document with some more lovely Dr. Seuss quotes..</Paragraph>
    </FlowDocument>
</FlowDocumentScrollViewer>