Inverted contextual toggle in sample; Fixed incorrect background during transition animation (again)

Microsoft.Toolkit.Uwp.SampleApp/SamplePages/TabbedCommandBar/TabbedCommandBar.bind

@@ -134,7 +134,7 @@
         </controls:TabbedCommandBar>
 
         <Grid Grid.Row="1">
-            <ToggleSwitch x:Name="ContextualToggle" IsOn="True"
+            <ToggleSwitch x:Name="ContextualToggle" IsOn="{Binding Visibility, ElementName=ShapeFormat, Mode=TwoWay}"
                           OffContent="Contextual Tab Off" OnContent="Contextual Tab On"/>
         </Grid>
     </Grid>

Microsoft.Toolkit.Uwp.UI.Controls/TabbedCommandBar/TabbedCommandBar.cs

@@ -84,7 +84,7 @@ namespace Microsoft.Toolkit.Uwp.UI.Controls
             _previousSelectedItem.RegisterPropertyChangedCallback(TabbedCommandBarItem.VisibilityProperty, SelectedItemVisibilityChanged);
 
             // Set the ribbon background and start the transition animation
-            _ribbonContentBorder.Background = item.Background;
+            //_ribbonContentBorder.Background = item.Background;
             _tabChangedStoryboard?.Begin();
         }
 

Microsoft.Toolkit.Uwp.UI.Controls/TabbedCommandBar/TabbedCommandBar.xaml

@@ -246,7 +246,7 @@
                         </Grid>
 
 
-                        <Border x:Name="PART_RibbonContentBorder" Grid.Row="1"
+                        <Border x:Name="PART_RibbonContentBorder" Grid.Row="1" Background="{Binding ElementName=PART_RibbonContent, Path=Content.Background}"
                                 VerticalAlignment="Stretch" HorizontalAlignment="Stretch">
                             <ContentControl x:Name="PART_RibbonContent" Content="{TemplateBinding SelectedItem}"
                                             HorizontalContentAlignment="Stretch">