<StackPanel>
    <CheckBox Name="IsDocumentEnabledChbk" Content="IsDocumentEnabled"/>
    <RichTextBox Name="richTB"
                 IsDocumentEnabled="{Binding ElementName=IsDocumentEnabledChbk,
                                             Path=IsChecked}">
        <FlowDocument>
            <Paragraph>
                Use the Checkbox above to switch between enabling and
                disabling the Button and Hyperlink in the RichTextBox.
                <Hyperlink>Here is a hyperlink</Hyperlink>
            </Paragraph>
            <BlockUIContainer>
                <Button>Click me!</Button>
            </BlockUIContainer>

        </FlowDocument>
    </RichTextBox>
</StackPanel>