Add ability to vertically align items in Backstage

[nlogozzo]

I followed issue #896 to align some items to the bottom of the backstage below is my xaml

<ribbon:Backstage>
    <Grid>
        <ribbon:BackstageTabControl>
             <ribbon:Button Header="Open"/>
         </ribbon:BackstageTabControl>

         <ribbon:BackstageTabControl VerticalAlignment="Bottom" Margin="0,0,0,4" IsBackButtonVisible="False">
             <ribbon:BackstageTabItem Header="Settings">
                  <ui:Frame Content="{Binding SettingsPage}"/>
              </ribbon:BackstageTabItem>
              <ribbon:Button Header="Exit" Click="BtnExit_Click"/>
         </ribbon:BackstageTabControl>
    </Grid>
</ribbon:Backstage>

However it ends up looking like this:

How can i get it so the items stay all the way at the bottom and for the settings page to take up the entire screen. Thanks in advanced

[batzen]

@nlogozzo You can easily achieve this starting with version 9.0 by setting VerticalAlignment="Bottom", DockPanel.Dock="Bottom" and if you want to align multiple items at the bottom invert their order (because of how DockPanel works).