ToolBar in a ToolBarTray

   
    

<Page xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      HorizontalAlignment="Stretch" VerticalAlignment="Top">
    <ToolBarTray>
      <ToolBar>
        <Button>Second toolbar</Button>
        <CheckBox IsChecked="True">Choice</CheckBox>
      </ToolBar>
    </ToolBarTray>
</Page>