FlowDocumentScrollViewer woes

Question

My goal is to have exandable sections in a flow document. This XAML works, BUT

1- if you change the root from grid to stackpanel the scrollbar no longer works.

2 - Exand section 1. Scrolldown and you'll see the Toolbar at the bottom and Section 2 below that - even tho IsToolBarVisible="False".

Perhaps I need to structure the FlowDocument different? Ideas? Pete

                <Grid x:Name="LayoutRoot">
                <FlowDocumentScrollViewer IsToolBarVisible="False">
                    <FlowDocument>
                        <Section  >
                            <BlockUIContainer>
                                <Expander Header="Section 1">
                                    <FlowDocument>
                                        <Paragraph>blah</Paragraph>
                                    </FlowDocument>
                                </Expander>
                            </BlockUIContainer>
                        </Section>
                        <Section  >
                            <BlockUIContainer>
                                <Expander Header="Section 2">
                                    <FlowDocument>
                                        <Paragraph>blah blah</Paragraph>
                                    </FlowDocument>
                                </Expander>
                            </BlockUIContainer>
                        </Section>


                    </FlowDocument>
                </FlowDocumentScrollViewer>
                </Grid>