Why are labels not showing in my QuickAccessToolbar?

In a nutshell, I need to provide a ribbon QuickAccessToolbar without the ribbon being visible. This is quite easily achieved, but a great problem for me is that the labels on the toolbar items are not visible. Here is my Ribbon:

<Ribbon x:Name="ShellRibbon" Grid.Row="0" IsMinimized="True">
    <Ribbon.QuickAccessToolBar>
        <RibbonQuickAccessToolBar>
            <RibbonSplitButton x:Name ="Save" Label="Save" />
            <RibbonSplitButton Label="Employee Access" LabelPosition="Header" >
                <RibbonMenuItem Header="Undo action #1" />
                <RibbonMenuItem Header="Undo action #2" />
                <RibbonMenuItem Header="Undo action #3" />
            </RibbonSplitButton>
        </RibbonQuickAccessToolBar>
    </Ribbon.QuickAccessToolBar>
    <RibbonTab>
        <RibbonButton Label="One"></RibbonButton>
    </RibbonTab>
    <RibbonTab></RibbonTab>
</Ribbon>

The RibbonMenuItem headers are visible when I drop down the RibbonSplitButton, but its header isn't visible, and neither that of the Save button. What am I doing wrong?

You have to place your ribbon controls inside a DockPanel :

<Ribbon.QuickAccessToolBar>
    <RibbonQuickAccessToolBar>
        <DockPanel>
            <RibbonSplitButton x:Name ="Save" Label="Save" />
            <RibbonSplitButton Label="Employee Access" LabelPosition="Header" >
                <RibbonMenuItem Header="Undo action #1" />
                <RibbonMenuItem Header="Undo action #2" />
                <RibbonMenuItem Header="Undo action #3" />
            </RibbonSplitButton>
        </DockPanel>
    </RibbonQuickAccessToolBar>
</Ribbon.QuickAccessToolBar>