From f01ebe19f60bb817dc8a09f6ea165d6004d3577b Mon Sep 17 00:00:00 2001
From: Martin Zikmund <martin@zikmund.dev>
Date: Wed, 25 Oct 2023 11:01:55 +0200
Subject: [PATCH] feat: Update TwoPaneView to winui3/release/1.4.2

---
 .../Version2/PriorityDefault/TwoPaneView.xaml | 200 +++-----
 .../themeresources_v2.xaml                    |  49 +-
 .../TwoPaneView/DisplayRegionHelper.Header.cs |   2 +-
 .../TwoPaneView/DisplayRegionHelper.cs        |   2 +-
 .../TwoPaneView/DisplayRegionHelperInfo.cs    |   2 +-
 .../TwoPaneView/DisplayRegionHelperTestApi.cs |   2 +-
 .../TwoPaneView/TwoPaneView.Header.cs         |   4 +-
 .../Xaml/Controls/TwoPaneView/TwoPaneView.cs  | 480 +++++++++---------
 .../Controls/TwoPaneView/TwoPaneViewMode.cs   |   2 +-
 .../TwoPaneView/TwoPaneViewPriority.cs        |   2 +-
 .../TwoPaneViewTallModeConfiguration.cs       |   2 +-
 .../TwoPaneViewWideModeConfiguration.cs       |   2 +-
 12 files changed, 333 insertions(+), 416 deletions(-)

diff --git a/src/Uno.UI.FluentTheme.v2/Resources/Version2/PriorityDefault/TwoPaneView.xaml b/src/Uno.UI.FluentTheme.v2/Resources/Version2/PriorityDefault/TwoPaneView.xaml
index caf1b2bb25d1..959e035b3140 100644
--- a/src/Uno.UI.FluentTheme.v2/Resources/Version2/PriorityDefault/TwoPaneView.xaml
+++ b/src/Uno.UI.FluentTheme.v2/Resources/Version2/PriorityDefault/TwoPaneView.xaml
@@ -1,130 +1,74 @@
 <!-- Copyright (c) Microsoft Corporation. All rights reserved. Licensed under the MIT License. See LICENSE in the project root for license information. -->
-<!-- MUX Reference TwoPaneView.xaml, commit a939567 -->
-<ResourceDictionary
-    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
-    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-    xmlns:local="using:Microsoft.UI.Xaml.Controls"
-    xmlns:contract7Present="http://schemas.microsoft.com/winfx/2006/xaml/presentation?IsApiContractPresent(Windows.Foundation.UniversalApiContract,7)"
-    xmlns:contract7NotPresent="http://schemas.microsoft.com/winfx/2006/xaml/presentation?IsApiContractNotPresent(Windows.Foundation.UniversalApiContract,7)">
-
-    <Style x:Key="DefaultTwoPaneViewStyle" TargetType="local:TwoPaneView">
-        <Setter Property="HorizontalAlignment" Value="Stretch" />
-        <Setter Property="VerticalAlignment" Value="Stretch" />
-        <Setter Property="MinWideModeWidth" Value="641"/>
-        <Setter Property="MinTallModeHeight" Value="641"/>
-        <Setter Property="IsTabStop" Value="False"/>
-        <Setter Property="Template">
-            <Setter.Value>
-                <ControlTemplate TargetType="local:TwoPaneView">
-                    <Grid x:Name="RootGrid" Background="{TemplateBinding Background}" HorizontalAlignment="Stretch" VerticalAlignment="Stretch">
-                        <VisualStateManager.VisualStateGroups>
-                            <VisualStateGroup x:Name="ModeStates">
-                                <VisualState x:Name="ViewMode_LeftRight"/>
-
-                                <VisualState x:Name="ViewMode_RightLeft">
-                                    <VisualState.Setters>
-                                        <contract7NotPresent:Setter Target="PART_Pane1.(Grid.Column)" Value="2"/>
-                                        <contract7NotPresent:Setter Target="PART_Pane2.(Grid.Column)" Value="0"/>
-
-                                        <contract7Present:Setter Target="PART_Pane1ScrollViewer.(Grid.Column)" Value="2"/>
-                                        <contract7Present:Setter Target="PART_Pane2ScrollViewer.(Grid.Column)" Value="0"/>
-                                    </VisualState.Setters>
-                                </VisualState>
-
-                                <VisualState x:Name="ViewMode_TopBottom">
-                                    <VisualState.Setters>
-                                        <contract7NotPresent:Setter Target="PART_Pane1.(Grid.Column)" Value="0"/>
-                                        <contract7NotPresent:Setter Target="PART_Pane1.(Grid.Row)" Value="0"/>
-
-                                        <contract7NotPresent:Setter Target="PART_Pane2.(Grid.Column)" Value="0"/>
-                                        <contract7NotPresent:Setter Target="PART_Pane2.(Grid.Row)" Value="2"/>
-
-                                        <contract7Present:Setter Target="PART_Pane1ScrollViewer.(Grid.Column)" Value="0"/>
-                                        <contract7Present:Setter Target="PART_Pane1ScrollViewer.(Grid.Row)" Value="0"/>
-
-                                        <contract7Present:Setter Target="PART_Pane2ScrollViewer.(Grid.Column)" Value="0"/>
-                                        <contract7Present:Setter Target="PART_Pane2ScrollViewer.(Grid.Row)" Value="2"/>
-                                    </VisualState.Setters>
-                                </VisualState>
-
-                                <VisualState x:Name="ViewMode_BottomTop">
-                                    <VisualState.Setters>
-                                        <contract7NotPresent:Setter Target="PART_Pane1.(Grid.Column)" Value="0"/>
-                                        <contract7NotPresent:Setter Target="PART_Pane1.(Grid.Row)" Value="2"/>
-
-                                        <contract7NotPresent:Setter Target="PART_Pane2.(Grid.Column)" Value="0"/>
-                                        <contract7NotPresent:Setter Target="PART_Pane2.(Grid.Row)" Value="0"/>
-
-                                        <contract7Present:Setter Target="PART_Pane1ScrollViewer.(Grid.Column)" Value="0"/>
-                                        <contract7Present:Setter Target="PART_Pane1ScrollViewer.(Grid.Row)" Value="2"/>
-
-                                        <contract7Present:Setter Target="PART_Pane2ScrollViewer.(Grid.Column)" Value="0"/>
-                                        <contract7Present:Setter Target="PART_Pane2ScrollViewer.(Grid.Row)" Value="0"/>
-                                    </VisualState.Setters>
-                                </VisualState>
-
-                                <VisualState x:Name="ViewMode_OneOnly">
-                                    <VisualState.Setters>
-                                        <contract7NotPresent:Setter Target="PART_Pane2.Visibility" Value="Collapsed"/>
-
-                                        <contract7Present:Setter Target="PART_Pane2ScrollViewer.Visibility" Value="Collapsed"/>
-                                    </VisualState.Setters>
-                                </VisualState>
-
-                                <VisualState x:Name="ViewMode_TwoOnly">
-                                    <VisualState.Setters>
-                                        <contract7NotPresent:Setter Target="PART_Pane1.Visibility" Value="Collapsed"/>
-                                        <contract7NotPresent:Setter Target="PART_Pane2.(Grid.Column)" Value="0"/>
-
-                                        <contract7Present:Setter Target="PART_Pane1ScrollViewer.Visibility" Value="Collapsed"/>
-                                        <contract7Present:Setter Target="PART_Pane2ScrollViewer.(Grid.Column)" Value="0"/>
-                                    </VisualState.Setters>
-                                </VisualState>
-                            </VisualStateGroup>
-                        </VisualStateManager.VisualStateGroups>
-
-                        <Grid.ColumnDefinitions>
-                            <ColumnDefinition x:Name="PART_ColumnLeft" Width="Auto"/>
-                            <ColumnDefinition x:Name="PART_ColumnMiddle" Width="0"/>
-                            <ColumnDefinition x:Name="PART_ColumnRight" Width="*"/>
-                        </Grid.ColumnDefinitions>
-
-                        <Grid.RowDefinitions>
-                            <RowDefinition x:Name="PART_RowTop" Height="*"/>
-                            <RowDefinition x:Name="PART_RowMiddle" Height="0"/>
-                            <RowDefinition x:Name="PART_RowBottom" Height="0"/>
-                        </Grid.RowDefinitions>
-
-                        <contract7Present:ScrollViewer
-                                x:Name="PART_Pane1ScrollViewer"
-                                Grid.Column="0"
-                                VerticalScrollBarVisibility="Auto">
-                            <Border Child="{TemplateBinding Pane1}" />
-                        </contract7Present:ScrollViewer>
-
-                        <contract7Present:ScrollViewer
-                                x:Name="PART_Pane2ScrollViewer"
-                                Grid.Column="2"
-                                VerticalScrollBarVisibility="Auto">
-                            <Border Child="{TemplateBinding Pane2}" />
-                        </contract7Present:ScrollViewer>
-
-                        <contract7NotPresent:Border
-                            x:Name="PART_Pane1"
-                            Grid.Column="0"
-                            Child="{TemplateBinding Pane1}"/>
-
-                        <contract7NotPresent:Border
-                            x:Name="PART_Pane2"
-                            Grid.Column="2"
-                            Child="{TemplateBinding Pane2}"/>
-
-                    </Grid>
-                </ControlTemplate>
-            </Setter.Value>
-        </Setter>
+<!-- MUX Reference TwoPaneView.xaml, tag winui3/release/1.4.2 -->
+<ResourceDictionary xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:controls="using:Microsoft.UI.Xaml.Controls" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
+    <Style x:Key="DefaultTwoPaneViewStyle" TargetType="controls:TwoPaneView">
+      <Setter Property="HorizontalAlignment" Value="Stretch" />
+      <Setter Property="VerticalAlignment" Value="Stretch" />
+      <Setter Property="MinWideModeWidth" Value="641" />
+      <Setter Property="MinTallModeHeight" Value="641" />
+      <Setter Property="IsTabStop" Value="False" />
+      <Setter Property="Template">
+        <Setter.Value>
+          <ControlTemplate TargetType="controls:TwoPaneView">
+            <Grid x:Name="RootGrid" Background="{TemplateBinding Background}" HorizontalAlignment="Stretch" VerticalAlignment="Stretch">
+              <VisualStateManager.VisualStateGroups>
+                <VisualStateGroup x:Name="ModeStates">
+                  <VisualState x:Name="ViewMode_LeftRight" />
+                  <VisualState x:Name="ViewMode_RightLeft">
+                    <VisualState.Setters>
+                      <Setter Target="PART_Pane1ScrollViewer.(Grid.Column)" Value="2" />
+                      <Setter Target="PART_Pane2ScrollViewer.(Grid.Column)" Value="0" />
+                    </VisualState.Setters>
+                  </VisualState>
+                  <VisualState x:Name="ViewMode_TopBottom">
+                    <VisualState.Setters>
+                      <Setter Target="PART_Pane1ScrollViewer.(Grid.Column)" Value="0" />
+                      <Setter Target="PART_Pane1ScrollViewer.(Grid.Row)" Value="0" />
+                      <Setter Target="PART_Pane2ScrollViewer.(Grid.Column)" Value="0" />
+                      <Setter Target="PART_Pane2ScrollViewer.(Grid.Row)" Value="2" />
+                    </VisualState.Setters>
+                  </VisualState>
+                  <VisualState x:Name="ViewMode_BottomTop">
+                    <VisualState.Setters>
+                      <Setter Target="PART_Pane1ScrollViewer.(Grid.Column)" Value="0" />
+                      <Setter Target="PART_Pane1ScrollViewer.(Grid.Row)" Value="2" />
+                      <Setter Target="PART_Pane2ScrollViewer.(Grid.Column)" Value="0" />
+                      <Setter Target="PART_Pane2ScrollViewer.(Grid.Row)" Value="0" />
+                    </VisualState.Setters>
+                  </VisualState>
+                  <VisualState x:Name="ViewMode_OneOnly">
+                    <VisualState.Setters>
+                      <Setter Target="PART_Pane2ScrollViewer.Visibility" Value="Collapsed" />
+                    </VisualState.Setters>
+                  </VisualState>
+                  <VisualState x:Name="ViewMode_TwoOnly">
+                    <VisualState.Setters>
+                      <Setter Target="PART_Pane1ScrollViewer.Visibility" Value="Collapsed" />
+                      <Setter Target="PART_Pane2ScrollViewer.(Grid.Column)" Value="0" />
+                    </VisualState.Setters>
+                  </VisualState>
+                </VisualStateGroup>
+              </VisualStateManager.VisualStateGroups>
+              <Grid.ColumnDefinitions>
+                <ColumnDefinition x:Name="PART_ColumnLeft" Width="Auto" />
+                <ColumnDefinition x:Name="PART_ColumnMiddle" Width="0" />
+                <ColumnDefinition x:Name="PART_ColumnRight" Width="*" />
+              </Grid.ColumnDefinitions>
+              <Grid.RowDefinitions>
+                <RowDefinition x:Name="PART_RowTop" Height="*" />
+                <RowDefinition x:Name="PART_RowMiddle" Height="0" />
+                <RowDefinition x:Name="PART_RowBottom" Height="0" />
+              </Grid.RowDefinitions>
+              <ScrollViewer x:Name="PART_Pane1ScrollViewer" Grid.Column="0" VerticalScrollBarVisibility="Auto">
+                <Border Child="{TemplateBinding Pane1}" />
+              </ScrollViewer>
+              <ScrollViewer x:Name="PART_Pane2ScrollViewer" Grid.Column="2" VerticalScrollBarVisibility="Auto">
+                <Border Child="{TemplateBinding Pane2}" />
+              </ScrollViewer>
+            </Grid>
+          </ControlTemplate>
+        </Setter.Value>
+      </Setter>
     </Style>
-
-    <Style TargetType="local:TwoPaneView" BasedOn="{StaticResource DefaultTwoPaneViewStyle}" />
-
-</ResourceDictionary>
\ No newline at end of file
+    <Style TargetType="controls:TwoPaneView" BasedOn="{StaticResource DefaultTwoPaneViewStyle}" />
+  </ResourceDictionary>
\ No newline at end of file
diff --git a/src/Uno.UI.FluentTheme.v2/themeresources_v2.xaml b/src/Uno.UI.FluentTheme.v2/themeresources_v2.xaml
index e3687b147ca2..d46b54814fab 100644
--- a/src/Uno.UI.FluentTheme.v2/themeresources_v2.xaml
+++ b/src/Uno.UI.FluentTheme.v2/themeresources_v2.xaml
@@ -23881,48 +23881,35 @@
                 <VisualState x:Name="ViewMode_LeftRight" />
                 <VisualState x:Name="ViewMode_RightLeft">
                   <VisualState.Setters>
-                    <contract7NotPresent:Setter Target="PART_Pane1.(Grid.Column)" Value="2" />
-                    <contract7NotPresent:Setter Target="PART_Pane2.(Grid.Column)" Value="0" />
-                    <contract7Present:Setter Target="PART_Pane1ScrollViewer.(Grid.Column)" Value="2" />
-                    <contract7Present:Setter Target="PART_Pane2ScrollViewer.(Grid.Column)" Value="0" />
+                    <Setter Target="PART_Pane1ScrollViewer.(Grid.Column)" Value="2" />
+                    <Setter Target="PART_Pane2ScrollViewer.(Grid.Column)" Value="0" />
                   </VisualState.Setters>
                 </VisualState>
                 <VisualState x:Name="ViewMode_TopBottom">
                   <VisualState.Setters>
-                    <contract7NotPresent:Setter Target="PART_Pane1.(Grid.Column)" Value="0" />
-                    <contract7NotPresent:Setter Target="PART_Pane1.(Grid.Row)" Value="0" />
-                    <contract7NotPresent:Setter Target="PART_Pane2.(Grid.Column)" Value="0" />
-                    <contract7NotPresent:Setter Target="PART_Pane2.(Grid.Row)" Value="2" />
-                    <contract7Present:Setter Target="PART_Pane1ScrollViewer.(Grid.Column)" Value="0" />
-                    <contract7Present:Setter Target="PART_Pane1ScrollViewer.(Grid.Row)" Value="0" />
-                    <contract7Present:Setter Target="PART_Pane2ScrollViewer.(Grid.Column)" Value="0" />
-                    <contract7Present:Setter Target="PART_Pane2ScrollViewer.(Grid.Row)" Value="2" />
+                    <Setter Target="PART_Pane1ScrollViewer.(Grid.Column)" Value="0" />
+                    <Setter Target="PART_Pane1ScrollViewer.(Grid.Row)" Value="0" />
+                    <Setter Target="PART_Pane2ScrollViewer.(Grid.Column)" Value="0" />
+                    <Setter Target="PART_Pane2ScrollViewer.(Grid.Row)" Value="2" />
                   </VisualState.Setters>
                 </VisualState>
                 <VisualState x:Name="ViewMode_BottomTop">
                   <VisualState.Setters>
-                    <contract7NotPresent:Setter Target="PART_Pane1.(Grid.Column)" Value="0" />
-                    <contract7NotPresent:Setter Target="PART_Pane1.(Grid.Row)" Value="2" />
-                    <contract7NotPresent:Setter Target="PART_Pane2.(Grid.Column)" Value="0" />
-                    <contract7NotPresent:Setter Target="PART_Pane2.(Grid.Row)" Value="0" />
-                    <contract7Present:Setter Target="PART_Pane1ScrollViewer.(Grid.Column)" Value="0" />
-                    <contract7Present:Setter Target="PART_Pane1ScrollViewer.(Grid.Row)" Value="2" />
-                    <contract7Present:Setter Target="PART_Pane2ScrollViewer.(Grid.Column)" Value="0" />
-                    <contract7Present:Setter Target="PART_Pane2ScrollViewer.(Grid.Row)" Value="0" />
+                    <Setter Target="PART_Pane1ScrollViewer.(Grid.Column)" Value="0" />
+                    <Setter Target="PART_Pane1ScrollViewer.(Grid.Row)" Value="2" />
+                    <Setter Target="PART_Pane2ScrollViewer.(Grid.Column)" Value="0" />
+                    <Setter Target="PART_Pane2ScrollViewer.(Grid.Row)" Value="0" />
                   </VisualState.Setters>
                 </VisualState>
                 <VisualState x:Name="ViewMode_OneOnly">
                   <VisualState.Setters>
-                    <contract7NotPresent:Setter Target="PART_Pane2.Visibility" Value="Collapsed" />
-                    <contract7Present:Setter Target="PART_Pane2ScrollViewer.Visibility" Value="Collapsed" />
+                    <Setter Target="PART_Pane2ScrollViewer.Visibility" Value="Collapsed" />
                   </VisualState.Setters>
                 </VisualState>
                 <VisualState x:Name="ViewMode_TwoOnly">
                   <VisualState.Setters>
-                    <contract7NotPresent:Setter Target="PART_Pane1.Visibility" Value="Collapsed" />
-                    <contract7NotPresent:Setter Target="PART_Pane2.(Grid.Column)" Value="0" />
-                    <contract7Present:Setter Target="PART_Pane1ScrollViewer.Visibility" Value="Collapsed" />
-                    <contract7Present:Setter Target="PART_Pane2ScrollViewer.(Grid.Column)" Value="0" />
+                    <Setter Target="PART_Pane1ScrollViewer.Visibility" Value="Collapsed" />
+                    <Setter Target="PART_Pane2ScrollViewer.(Grid.Column)" Value="0" />
                   </VisualState.Setters>
                 </VisualState>
               </VisualStateGroup>
@@ -23937,14 +23924,12 @@
               <RowDefinition x:Name="PART_RowMiddle" Height="0" />
               <RowDefinition x:Name="PART_RowBottom" Height="0" />
             </Grid.RowDefinitions>
-            <contract7Present:ScrollViewer x:Name="PART_Pane1ScrollViewer" Grid.Column="0" VerticalScrollBarVisibility="Auto">
+            <ScrollViewer x:Name="PART_Pane1ScrollViewer" Grid.Column="0" VerticalScrollBarVisibility="Auto">
               <Border Child="{TemplateBinding Pane1}" />
-            </contract7Present:ScrollViewer>
-            <contract7Present:ScrollViewer x:Name="PART_Pane2ScrollViewer" Grid.Column="2" VerticalScrollBarVisibility="Auto">
+            </ScrollViewer>
+            <ScrollViewer x:Name="PART_Pane2ScrollViewer" Grid.Column="2" VerticalScrollBarVisibility="Auto">
               <Border Child="{TemplateBinding Pane2}" />
-            </contract7Present:ScrollViewer>
-            <contract7NotPresent:Border x:Name="PART_Pane1" Grid.Column="0" Child="{TemplateBinding Pane1}" />
-            <contract7NotPresent:Border x:Name="PART_Pane2" Grid.Column="2" Child="{TemplateBinding Pane2}" />
+            </ScrollViewer>
           </Grid>
         </ControlTemplate>
       </Setter.Value>
diff --git a/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/DisplayRegionHelper.Header.cs b/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/DisplayRegionHelper.Header.cs
index 1473e54e41db..b34d2dc0d3fc 100644
--- a/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/DisplayRegionHelper.Header.cs
+++ b/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/DisplayRegionHelper.Header.cs
@@ -1,6 +1,6 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License. See LICENSE in the project root for license information.
-// MUX Reference DisplayRegionHelper.h, commit d876b4e
+// MUX Reference DisplayRegionHelper.h, tag winui3/release/1.4.2
 
 #nullable enable
 
diff --git a/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/DisplayRegionHelper.cs b/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/DisplayRegionHelper.cs
index 5170b4668f1e..b8a767d3f2da 100644
--- a/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/DisplayRegionHelper.cs
+++ b/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/DisplayRegionHelper.cs
@@ -1,6 +1,6 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License. See LICENSE in the project root for license information.
-// MUX Reference DisplayRegionHelper.cpp, commit 45e6a3f
+// MUX Reference DisplayRegionHelper.cpp, tag winui3/release/1.4.2
 
 using Uno.UI;
 using Uno.UI.Helpers.WinUI;
diff --git a/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/DisplayRegionHelperInfo.cs b/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/DisplayRegionHelperInfo.cs
index 765e96f01e44..2453150c4620 100644
--- a/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/DisplayRegionHelperInfo.cs
+++ b/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/DisplayRegionHelperInfo.cs
@@ -1,6 +1,6 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License. See LICENSE in the project root for license information.
-// MUX Reference DisplayRegionHelper.h, commit d876b4e
+// MUX Reference DisplayRegionHelper.h, tag winui3/release/1.4.2
 
 #nullable enable
 
diff --git a/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/DisplayRegionHelperTestApi.cs b/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/DisplayRegionHelperTestApi.cs
index 08035a5cf90c..29f186764061 100644
--- a/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/DisplayRegionHelperTestApi.cs
+++ b/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/DisplayRegionHelperTestApi.cs
@@ -1,6 +1,6 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License. See LICENSE in the project root for license information.
-// MUX Reference DisplayRegionHelperTestApi.cpp, commit d883cf3
+// MUX Reference DisplayRegionHelperTestApi.cpp, tag winui3/release/1.4.2
 
 namespace Microsoft.UI.Xaml.Controls;
 
diff --git a/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/TwoPaneView.Header.cs b/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/TwoPaneView.Header.cs
index f6a7b8b318a4..028309dd7a15 100644
--- a/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/TwoPaneView.Header.cs
+++ b/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/TwoPaneView.Header.cs
@@ -1,6 +1,6 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License. See LICENSE in the project root for license information.
-// MUX Reference TwoPaneView.h, commit b3a2e45
+// MUX Reference TwoPaneView.h, tag winui3/release/1.4.2
 
 #nullable enable
 
@@ -42,5 +42,5 @@ private enum ViewMode
 	private RowDefinition? m_rowTop = null;
 	private RowDefinition? m_rowMiddle = null;
 	private RowDefinition? m_rowBottom = null;
-	private readonly SerialDisposable m_windowSizeChangedRevoker = new();
+	private readonly SerialDisposable m_xamlRootChangedRevoker = new();
 }
diff --git a/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/TwoPaneView.cs b/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/TwoPaneView.cs
index 26c9b9c8ed3b..922a32ca496a 100644
--- a/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/TwoPaneView.cs
+++ b/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/TwoPaneView.cs
@@ -1,6 +1,6 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License. See LICENSE in the project root for license information.
-// MUX Reference TwoPaneView.properties.cpp, commit 4be817e
+// MUX Reference TwoPaneView.properties.cpp, tag winui3/release/1.4.2
 
 using System;
 using Uno.Disposables;
@@ -10,325 +10,313 @@
 using Windows.UI.Xaml.Controls;
 using Windows.UI.Xaml.Media;
 
-#if HAS_UNO_WINUI
-using WindowSizeChangedEventArgs = Microsoft.UI.Xaml.WindowSizeChangedEventArgs;
-#else
-using WindowSizeChangedEventArgs = Windows.UI.Core.WindowSizeChangedEventArgs;
-#endif
+namespace Microsoft.UI.Xaml.Controls;
 
-namespace Microsoft.UI.Xaml.Controls
+/// <summary>
+/// Represents a container with two views that size and position content
+/// in the available space, either side-by-side or top-bottom.
+/// </summary>
+public partial class TwoPaneView : Windows.UI.Xaml.Controls.Control
 {
+	private const string c_pane1ScrollViewerName = "PART_Pane1ScrollViewer";
+	private const string c_pane2ScrollViewerName = "PART_Pane2ScrollViewer";
+
+	private const string c_columnLeftName = "PART_ColumnLeft";
+	private const string c_columnMiddleName = "PART_ColumnMiddle";
+	private const string c_columnRightName = "PART_ColumnRight";
+	private const string c_rowTopName = "PART_RowTop";
+	private const string c_rowMiddleName = "PART_RowMiddle";
+	private const string c_rowBottomName = "PART_RowBottom";
+
 	/// <summary>
-	/// Represents a container with two views that size and position content
-	/// in the available space, either side-by-side or top-bottom.
+	/// Initializes a new instance of the TwoPaneView class.
 	/// </summary>
-	public partial class TwoPaneView : Windows.UI.Xaml.Controls.Control
+	public TwoPaneView()
 	{
-		private const string c_pane1ScrollViewerName = "PART_Pane1ScrollViewer";
-		private const string c_pane2ScrollViewerName = "PART_Pane2ScrollViewer";
-
-		private const string c_columnLeftName = "PART_ColumnLeft";
-		private const string c_columnMiddleName = "PART_ColumnMiddle";
-		private const string c_columnRightName = "PART_ColumnRight";
-		private const string c_rowTopName = "PART_RowTop";
-		private const string c_rowMiddleName = "PART_RowMiddle";
-		private const string c_rowBottomName = "PART_RowBottom";
-
-		/// <summary>
-		/// Initializes a new instance of the TwoPaneView class.
-		/// </summary>
-		public TwoPaneView()
-		{
-			DefaultStyleKey = typeof(TwoPaneView);
+		DefaultStyleKey = typeof(TwoPaneView);
 
-			SizeChanged += OnSizeChanged;
-			var window = Windows.UI.Xaml.Window.Current;
-			window.SizeChanged += OnWindowSizeChanged;
-			m_windowSizeChangedRevoker.Disposable = Disposable.Create(() => window.SizeChanged -= OnWindowSizeChanged);
+		SizeChanged += OnSizeChanged;
 
-			// TODO Uno specific: Revoke events - https://github.com/microsoft/microsoft-ui-xaml/issues/6357
-			Unloaded += (s, e) =>
-			{
-				m_windowSizeChangedRevoker.Disposable = null;
-				m_pane1LoadedRevoker.Disposable = null;
-				m_pane2LoadedRevoker.Disposable = null;
-			};
-		}
-
-		protected override void OnApplyTemplate()
+		// TODO Uno specific: Revoke events - https://github.com/microsoft/microsoft-ui-xaml/issues/6357
+		Unloaded += (s, e) =>
 		{
-			m_loaded = true;
+			m_xamlRootChangedRevoker.Disposable = null;
+			m_pane1LoadedRevoker.Disposable = null;
+			m_pane2LoadedRevoker.Disposable = null;
+		};
+	}
 
-			SetScrollViewerProperties(c_pane1ScrollViewerName, m_pane1LoadedRevoker);
-			SetScrollViewerProperties(c_pane2ScrollViewerName, m_pane2LoadedRevoker);
+	protected override void OnApplyTemplate()
+	{
+		m_loaded = true;
 
-			if (GetTemplateChild(c_columnLeftName) is ColumnDefinition column)
-			{
-				m_columnLeft = column;
-			}
-			if (GetTemplateChild(c_columnMiddleName) is ColumnDefinition middleColumn)
-			{
-				m_columnMiddle = middleColumn;
-			}
-			if (GetTemplateChild(c_columnRightName) is ColumnDefinition columnRight)
-			{
-				m_columnRight = columnRight;
-			}
-			if (GetTemplateChild(c_rowTopName) is RowDefinition rowTop)
-			{
-				m_rowTop = rowTop;
-			}
-			if (GetTemplateChild(c_rowMiddleName) is RowDefinition rowMiddle)
-			{
-				m_rowMiddle = rowMiddle;
-			}
-			if (GetTemplateChild(c_rowBottomName) is RowDefinition rowBottom)
-			{
-				m_rowBottom = rowBottom;
-			}
+		var xamlRoot = XamlRoot;
+		xamlRoot!.Changed += OnXamlRootChanged;
+		m_xamlRootChangedRevoker.Disposable = Disposable.Create(() => xamlRoot!.Changed -= OnXamlRootChanged);
+
+		SetScrollViewerProperties(c_pane1ScrollViewerName, m_pane1LoadedRevoker);
+		SetScrollViewerProperties(c_pane2ScrollViewerName, m_pane2LoadedRevoker);
+
+		if (GetTemplateChild(c_columnLeftName) is ColumnDefinition column)
+		{
+			m_columnLeft = column;
+		}
+		if (GetTemplateChild(c_columnMiddleName) is ColumnDefinition middleColumn)
+		{
+			m_columnMiddle = middleColumn;
 		}
+		if (GetTemplateChild(c_columnRightName) is ColumnDefinition columnRight)
+		{
+			m_columnRight = columnRight;
+		}
+		if (GetTemplateChild(c_rowTopName) is RowDefinition rowTop)
+		{
+			m_rowTop = rowTop;
+		}
+		if (GetTemplateChild(c_rowMiddleName) is RowDefinition rowMiddle)
+		{
+			m_rowMiddle = rowMiddle;
+		}
+		if (GetTemplateChild(c_rowBottomName) is RowDefinition rowBottom)
+		{
+			m_rowBottom = rowBottom;
+		}
+	}
 
-		private void SetScrollViewerProperties(string scrollViewerName, SerialDisposable revoker)
+	private void SetScrollViewerProperties(string scrollViewerName, SerialDisposable revoker)
+	{
+		if (GetTemplateChild(scrollViewerName) is ScrollViewer scrollViewer)
 		{
-			if (SharedHelpers.IsRS5OrHigher())
-			{
-				if (GetTemplateChild(scrollViewerName) is ScrollViewer scrollViewer)
-				{
-					if (SharedHelpers.IsScrollContentPresenterSizesContentToTemplatedParentAvailable())
-					{
-						scrollViewer.Loaded += OnScrollViewerLoaded;
-						revoker.Disposable = Disposable.Create(() => scrollViewer.Loaded -= OnScrollViewerLoaded);
-					}
-				}
-			}
+			scrollViewer.Loaded += OnScrollViewerLoaded;
+			revoker.Disposable = Disposable.Create(() => scrollViewer.Loaded -= OnScrollViewerLoaded);
 		}
+	}
 
-		private void OnScrollViewerLoaded(object sender, RoutedEventArgs args)
+	private void OnScrollViewerLoaded(object sender, RoutedEventArgs args)
+	{
+		if (sender is FrameworkElement scrollViewer)
 		{
-			if (sender is FrameworkElement scrollViewer)
+			var scrollContentPresenterFE = SharedHelpers.FindInVisualTreeByName(scrollViewer, "ScrollContentPresenter");
+			if (scrollContentPresenterFE != null)
 			{
-				var scrollContentPresenterFE = SharedHelpers.FindInVisualTreeByName(scrollViewer, "ScrollContentPresenter");
-				if (scrollContentPresenterFE != null)
+				if (scrollContentPresenterFE is ScrollContentPresenter scrollContentPresenter)
 				{
-					if (scrollContentPresenterFE is ScrollContentPresenter scrollContentPresenter)
-					{
-						scrollContentPresenter.SizesContentToTemplatedParent = true;
-					}
+					scrollContentPresenter.SizesContentToTemplatedParent = true;
 				}
 			}
 		}
+	}
 
-		private void OnWindowSizeChanged(object sender, WindowSizeChangedEventArgs args)
-		{
-			UpdateMode();
-		}
+	private void OnXamlRootChanged(object sender, XamlRootChangedEventArgs args)
+	{
+		UpdateMode();
+	}
 
-		private void OnSizeChanged(object sender, SizeChangedEventArgs args)
-		{
-			UpdateMode();
-		}
+	private void OnSizeChanged(object sender, SizeChangedEventArgs args)
+	{
+		UpdateMode();
+	}
 
-		private void UpdateMode()
-		{
-			// Don't bother running this logic until after we hit OnApplyTemplate.
-			if (!m_loaded) return;
+	private void UpdateMode()
+	{
+		// Don't bother running this logic until after we hit OnApplyTemplate.
+		if (!m_loaded) return;
 
-			double controlWidth = ActualWidth;
-			double controlHeight = ActualHeight;
+		double controlWidth = ActualWidth;
+		double controlHeight = ActualHeight;
 
-			ViewMode newMode = (PanePriority == TwoPaneViewPriority.Pane1) ? ViewMode.Pane1Only : ViewMode.Pane2Only;
+		ViewMode newMode = (PanePriority == TwoPaneViewPriority.Pane1) ? ViewMode.Pane1Only : ViewMode.Pane2Only;
 
-			// Calculate new mode
-			DisplayRegionHelperInfo info = DisplayRegionHelper.GetRegionInfo();
-			Rect rcControl = GetControlRect();
-			bool isInMultipleRegions = IsInMultipleRegions(info, rcControl);
+		// Calculate new mode
+		DisplayRegionHelperInfo info = DisplayRegionHelper.GetRegionInfo();
+		Rect rcControl = GetControlRect();
+		bool isInMultipleRegions = IsInMultipleRegions(info, rcControl);
 
-			if (isInMultipleRegions)
+		if (isInMultipleRegions)
+		{
+			if (info.Mode == TwoPaneViewMode.Wide)
 			{
-				if (info.Mode == TwoPaneViewMode.Wide)
+				// Regions are laid out horizontally
+				if (WideModeConfiguration != TwoPaneViewWideModeConfiguration.SinglePane)
 				{
-					// Regions are laid out horizontally
-					if (WideModeConfiguration != TwoPaneViewWideModeConfiguration.SinglePane)
-					{
-						newMode = (WideModeConfiguration == TwoPaneViewWideModeConfiguration.LeftRight) ? ViewMode.LeftRight : ViewMode.RightLeft;
-					}
-				}
-				else if (info.Mode == TwoPaneViewMode.Tall)
-				{
-					// Regions are laid out vertically
-					if (TallModeConfiguration != TwoPaneViewTallModeConfiguration.SinglePane)
-					{
-						newMode = (TallModeConfiguration == TwoPaneViewTallModeConfiguration.TopBottom) ? ViewMode.TopBottom : ViewMode.BottomTop;
-					}
+					newMode = (WideModeConfiguration == TwoPaneViewWideModeConfiguration.LeftRight) ? ViewMode.LeftRight : ViewMode.RightLeft;
 				}
 			}
-			else
+			else if (info.Mode == TwoPaneViewMode.Tall)
 			{
-				// One region
-				if (controlWidth > MinWideModeWidth && WideModeConfiguration != TwoPaneViewWideModeConfiguration.SinglePane)
+				// Regions are laid out vertically
+				if (TallModeConfiguration != TwoPaneViewTallModeConfiguration.SinglePane)
 				{
-					// Split horizontally
-					newMode = (WideModeConfiguration == TwoPaneViewWideModeConfiguration.LeftRight) ? ViewMode.LeftRight : ViewMode.RightLeft;
-				}
-				else if (controlHeight > MinTallModeHeight && TallModeConfiguration != TwoPaneViewTallModeConfiguration.SinglePane)
-				{
-					// Split vertically
 					newMode = (TallModeConfiguration == TwoPaneViewTallModeConfiguration.TopBottom) ? ViewMode.TopBottom : ViewMode.BottomTop;
 				}
 			}
+		}
+		else
+		{
+			// One region
+			if (controlWidth > MinWideModeWidth && WideModeConfiguration != TwoPaneViewWideModeConfiguration.SinglePane)
+			{
+				// Split horizontally
+				newMode = (WideModeConfiguration == TwoPaneViewWideModeConfiguration.LeftRight) ? ViewMode.LeftRight : ViewMode.RightLeft;
+			}
+			else if (controlHeight > MinTallModeHeight && TallModeConfiguration != TwoPaneViewTallModeConfiguration.SinglePane)
+			{
+				// Split vertically
+				newMode = (TallModeConfiguration == TwoPaneViewTallModeConfiguration.TopBottom) ? ViewMode.TopBottom : ViewMode.BottomTop;
+			}
+		}
 
-			// Update row/column sizes (this may need to happen even if the mode doesn't change)
-			UpdateRowsColumns(newMode, info, rcControl);
+		// Update row/column sizes (this may need to happen even if the mode doesn't change)
+		UpdateRowsColumns(newMode, info, rcControl);
 
-			// Update mode if necessary
-			if (newMode != m_currentMode)
-			{
-				m_currentMode = newMode;
+		// Update mode if necessary
+		if (newMode != m_currentMode)
+		{
+			m_currentMode = newMode;
 
-				TwoPaneViewMode newViewMode = TwoPaneViewMode.SinglePane;
+			TwoPaneViewMode newViewMode = TwoPaneViewMode.SinglePane;
 
-				switch (m_currentMode)
-				{
-					case ViewMode.Pane1Only: VisualStateManager.GoToState(this, "ViewMode_OneOnly", true); break;
-					case ViewMode.Pane2Only: VisualStateManager.GoToState(this, "ViewMode_TwoOnly", true); break;
-					case ViewMode.LeftRight: VisualStateManager.GoToState(this, "ViewMode_LeftRight", true); newViewMode = TwoPaneViewMode.Wide; break;
-					case ViewMode.RightLeft: VisualStateManager.GoToState(this, "ViewMode_RightLeft", true); newViewMode = TwoPaneViewMode.Wide; break;
-					case ViewMode.TopBottom: VisualStateManager.GoToState(this, "ViewMode_TopBottom", true); newViewMode = TwoPaneViewMode.Tall; break;
-					case ViewMode.BottomTop: VisualStateManager.GoToState(this, "ViewMode_BottomTop", true); newViewMode = TwoPaneViewMode.Tall; break;
-				}
+			switch (m_currentMode)
+			{
+				case ViewMode.Pane1Only: VisualStateManager.GoToState(this, "ViewMode_OneOnly", true); break;
+				case ViewMode.Pane2Only: VisualStateManager.GoToState(this, "ViewMode_TwoOnly", true); break;
+				case ViewMode.LeftRight: VisualStateManager.GoToState(this, "ViewMode_LeftRight", true); newViewMode = TwoPaneViewMode.Wide; break;
+				case ViewMode.RightLeft: VisualStateManager.GoToState(this, "ViewMode_RightLeft", true); newViewMode = TwoPaneViewMode.Wide; break;
+				case ViewMode.TopBottom: VisualStateManager.GoToState(this, "ViewMode_TopBottom", true); newViewMode = TwoPaneViewMode.Tall; break;
+				case ViewMode.BottomTop: VisualStateManager.GoToState(this, "ViewMode_BottomTop", true); newViewMode = TwoPaneViewMode.Tall; break;
+			}
 
-				if (newViewMode != Mode)
-				{
-					SetValue(ModeProperty, newViewMode);
-					ModeChanged?.Invoke(this, this);
-				}
+			if (newViewMode != Mode)
+			{
+				SetValue(ModeProperty, newViewMode);
+				ModeChanged?.Invoke(this, this);
 			}
 		}
+	}
 
-		private void UpdateRowsColumns(ViewMode newMode, DisplayRegionHelperInfo info, Rect rcControl)
+	private void UpdateRowsColumns(ViewMode newMode, DisplayRegionHelperInfo info, Rect rcControl)
+	{
+		if (m_columnLeft != null && m_columnMiddle != null && m_columnRight != null && m_rowTop != null && m_rowMiddle != null && m_rowBottom != null)
 		{
-			if (m_columnLeft != null && m_columnMiddle != null && m_columnRight != null && m_rowTop != null && m_rowMiddle != null && m_rowBottom != null)
+			// Reset split lengths
+			m_columnMiddle.Width = new GridLength(0, GridUnitType.Pixel);
+			m_rowMiddle.Height = new GridLength(0, GridUnitType.Pixel);
+
+			// Set columns lengths
+			if (newMode == ViewMode.LeftRight || newMode == ViewMode.RightLeft)
+			{
+				m_columnLeft.Width = (newMode == ViewMode.LeftRight) ? Pane1Length : Pane2Length;
+				m_columnRight.Width = (newMode == ViewMode.LeftRight) ? Pane2Length : Pane1Length;
+			}
+			else
 			{
-				// Reset split lengths
-				m_columnMiddle.Width = new GridLength(0, GridUnitType.Pixel);
-				m_rowMiddle.Height = new GridLength(0, GridUnitType.Pixel);
+				m_columnLeft.Width = new GridLength(1, GridUnitType.Star);
+				m_columnRight.Width = new GridLength(0, GridUnitType.Pixel);
+			}
 
-				// Set columns lengths
-				if (newMode == ViewMode.LeftRight || newMode == ViewMode.RightLeft)
-				{
-					m_columnLeft.Width = (newMode == ViewMode.LeftRight) ? Pane1Length : Pane2Length;
-					m_columnRight.Width = (newMode == ViewMode.LeftRight) ? Pane2Length : Pane1Length;
-				}
-				else
-				{
-					m_columnLeft.Width = new GridLength(1, GridUnitType.Star);
-					m_columnRight.Width = new GridLength(0, GridUnitType.Pixel);
-				}
+			// Set row lengths
+			if (newMode == ViewMode.TopBottom || newMode == ViewMode.BottomTop)
+			{
+				m_rowTop.Height = (newMode == ViewMode.TopBottom) ? Pane1Length : Pane2Length;
+				m_rowBottom.Height = (newMode == ViewMode.TopBottom) ? Pane2Length : Pane1Length;
+			}
+			else
+			{
+				m_rowTop.Height = new GridLength(1, GridUnitType.Star);
+				m_rowBottom.Height = new GridLength(0, GridUnitType.Pixel);
+			}
 
-				// Set row lengths
-				if (newMode == ViewMode.TopBottom || newMode == ViewMode.BottomTop)
-				{
-					m_rowTop.Height = (newMode == ViewMode.TopBottom) ? Pane1Length : Pane2Length;
-					m_rowBottom.Height = (newMode == ViewMode.TopBottom) ? Pane2Length : Pane1Length;
-				}
-				else
-				{
-					m_rowTop.Height = new GridLength(1, GridUnitType.Star);
-					m_rowBottom.Height = new GridLength(0, GridUnitType.Pixel);
-				}
+			// Handle regions
+			if (IsInMultipleRegions(info, rcControl) && newMode != ViewMode.Pane1Only && newMode != ViewMode.Pane2Only)
+			{
+				Rect rc1 = info.Regions[0];
+				Rect rc2 = info.Regions[1];
+				Rect rcWindow = DisplayRegionHelper.WindowRect();
 
-				// Handle regions
-				if (IsInMultipleRegions(info, rcControl) && newMode != ViewMode.Pane1Only && newMode != ViewMode.Pane2Only)
+				if (info.Mode == TwoPaneViewMode.Wide)
 				{
-					Rect rc1 = info.Regions[0];
-					Rect rc2 = info.Regions[1];
-					Rect rcWindow = DisplayRegionHelper.WindowRect();
+					m_columnMiddle.Width = new GridLength(rc2.X - rc1.Width, GridUnitType.Pixel);
 
-					if (info.Mode == TwoPaneViewMode.Wide)
-					{
-						m_columnMiddle.Width = new GridLength(rc2.X - rc1.Width, GridUnitType.Pixel);
+					m_columnLeft.Width = new GridLength(rc1.Width - rcControl.X, GridUnitType.Pixel);
 
-						m_columnLeft.Width = new GridLength(rc1.Width - rcControl.X, GridUnitType.Pixel);
-
-						// UNO TODO: Max is needed when regions don't match the Window size orientation
-						m_columnRight.Width = new GridLength(Math.Max(0, rc2.Width - ((rcWindow.Width - rcControl.Width) - rcControl.X)), GridUnitType.Pixel);
-					}
-					else
-					{
-						m_rowMiddle.Height = new GridLength(rc2.Y - rc1.Height, GridUnitType.Pixel);
+					// UNO TODO: Max is needed when regions don't match the Window size orientation
+					m_columnRight.Width = new GridLength(Math.Max(0, rc2.Width - ((rcWindow.Width - rcControl.Width) - rcControl.X)), GridUnitType.Pixel);
+				}
+				else
+				{
+					m_rowMiddle.Height = new GridLength(rc2.Y - rc1.Height, GridUnitType.Pixel);
 
-						m_rowTop.Height = new GridLength(rc1.Height - rcControl.Y, GridUnitType.Pixel);
+					m_rowTop.Height = new GridLength(rc1.Height - rcControl.Y, GridUnitType.Pixel);
 
-						// UNO TODO: Max is needed when regions don't match the Window size orientation
-						m_rowBottom.Height = new GridLength(Math.Max(0, rc2.Height - ((rcWindow.Height - rcControl.Height) - rcControl.Y)), GridUnitType.Pixel);
-					}
+					// UNO TODO: Max is needed when regions don't match the Window size orientation
+					m_rowBottom.Height = new GridLength(Math.Max(0, rc2.Height - ((rcWindow.Height - rcControl.Height) - rcControl.Y)), GridUnitType.Pixel);
 				}
 			}
 		}
+	}
 
-		private Rect GetControlRect()
-		{
-			// Find out where this control is in the window
-			GeneralTransform transform = TransformToVisual(DisplayRegionHelper.WindowElement());
-			return transform.TransformBounds(new Rect(0, 0, (float)ActualWidth, (float)ActualHeight));
-		}
+	private Rect GetControlRect()
+	{
+		// Find out where this control is in the window
+		GeneralTransform transform = TransformToVisual(DisplayRegionHelper.WindowElement());
+		return transform.TransformBounds(new Rect(0, 0, (float)ActualWidth, (float)ActualHeight));
+	}
+
+	private bool IsInMultipleRegions(DisplayRegionHelperInfo info, Rect rcControl)
+	{
+		bool isInMultipleRegions = false;
 
-		private bool IsInMultipleRegions(DisplayRegionHelperInfo info, Rect rcControl)
+		if (info.Mode != TwoPaneViewMode.SinglePane)
 		{
-			bool isInMultipleRegions = false;
+			Rect rc1 = info.Regions[0];
+			Rect rc2 = info.Regions[1];
 
-			if (info.Mode != TwoPaneViewMode.SinglePane)
+			if (info.Mode == TwoPaneViewMode.Wide)
 			{
-				Rect rc1 = info.Regions[0];
-				Rect rc2 = info.Regions[1];
-
-				if (info.Mode == TwoPaneViewMode.Wide)
+				// Check that the control is over the split
+				if (rcControl.X < rc1.Width && rcControl.X + rcControl.Width > rc2.X)
 				{
-					// Check that the control is over the split
-					if (rcControl.X < rc1.Width && rcControl.X + rcControl.Width > rc2.X)
-					{
-						isInMultipleRegions = true;
-					}
+					isInMultipleRegions = true;
 				}
-				else if (info.Mode == TwoPaneViewMode.Tall)
+			}
+			else if (info.Mode == TwoPaneViewMode.Tall)
+			{
+				// Check that the control is over the split
+				if (rcControl.Y < rc1.Height && rcControl.Y + rcControl.Height > rc2.Y)
 				{
-					// Check that the control is over the split
-					if (rcControl.Y < rc1.Height && rcControl.Y + rcControl.Height > rc2.Y)
-					{
-						isInMultipleRegions = true;
-					}
+					isInMultipleRegions = true;
 				}
 			}
-
-			return isInMultipleRegions;
 		}
 
-		private void OnPropertyChanged(DependencyPropertyChangedEventArgs args)
-		{
-			var property = args.Property;
+		return isInMultipleRegions;
+	}
 
-			// Clamp property values -- early return if the values were clamped as we'll come back with the new value.
-			if (property == MinWideModeWidthProperty || property == MinTallModeHeightProperty)
-			{
-				var value = (double)args.NewValue;
-				var clampedValue = Math.Max(0.0, value);
-				if (clampedValue != value)
-				{
-					SetValue(property, clampedValue);
-					return;
-				}
-			}
+	private void OnPropertyChanged(DependencyPropertyChangedEventArgs args)
+	{
+		var property = args.Property;
 
-			if (property == PanePriorityProperty
-				|| property == Pane1LengthProperty
-				|| property == Pane2LengthProperty
-				|| property == WideModeConfigurationProperty
-				|| property == TallModeConfigurationProperty
-				|| property == MinWideModeWidthProperty
-				|| property == MinTallModeHeightProperty)
+		// Clamp property values -- early return if the values were clamped as we'll come back with the new value.
+		if (property == MinWideModeWidthProperty || property == MinTallModeHeightProperty)
+		{
+			var value = (double)args.NewValue;
+			var clampedValue = Math.Max(0.0, value);
+			if (clampedValue != value)
 			{
-				UpdateMode();
+				SetValue(property, clampedValue);
+				return;
 			}
 		}
+
+		if (property == PanePriorityProperty
+			|| property == Pane1LengthProperty
+			|| property == Pane2LengthProperty
+			|| property == WideModeConfigurationProperty
+			|| property == TallModeConfigurationProperty
+			|| property == MinWideModeWidthProperty
+			|| property == MinTallModeHeightProperty)
+		{
+			UpdateMode();
+		}
 	}
 }
diff --git a/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/TwoPaneViewMode.cs b/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/TwoPaneViewMode.cs
index 6b3c00e9f6c1..127851192937 100644
--- a/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/TwoPaneViewMode.cs
+++ b/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/TwoPaneViewMode.cs
@@ -1,6 +1,6 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License. See LICENSE in the project root for license information.
-// MUX Reference TwoPaneView.idl, commit c6174f1
+// MUX Reference TwoPaneView.idl, tag winui3/release/1.4.2
 
 namespace Microsoft.UI.Xaml.Controls;
 
diff --git a/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/TwoPaneViewPriority.cs b/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/TwoPaneViewPriority.cs
index f78b45517242..8f315d8d4bb7 100644
--- a/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/TwoPaneViewPriority.cs
+++ b/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/TwoPaneViewPriority.cs
@@ -1,6 +1,6 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License. See LICENSE in the project root for license information.
-// MUX Reference TwoPaneView.idl, commit c6174f1
+// MUX Reference TwoPaneView.idl, tag winui3/release/1.4.2
 
 namespace Microsoft.UI.Xaml.Controls;
 
diff --git a/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/TwoPaneViewTallModeConfiguration.cs b/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/TwoPaneViewTallModeConfiguration.cs
index 6bc91f17ed89..f2ed8ecb2bce 100644
--- a/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/TwoPaneViewTallModeConfiguration.cs
+++ b/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/TwoPaneViewTallModeConfiguration.cs
@@ -1,6 +1,6 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License. See LICENSE in the project root for license information.
-// MUX Reference TwoPaneView.idl, commit c6174f1
+// MUX Reference TwoPaneView.idl, tag winui3/release/1.4.2
 
 namespace Microsoft.UI.Xaml.Controls;
 
diff --git a/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/TwoPaneViewWideModeConfiguration.cs b/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/TwoPaneViewWideModeConfiguration.cs
index f56a5c94cf57..a080868deae5 100644
--- a/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/TwoPaneViewWideModeConfiguration.cs
+++ b/src/Uno.UI/Microsoft/UI/Xaml/Controls/TwoPaneView/TwoPaneViewWideModeConfiguration.cs
@@ -1,6 +1,6 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License. See LICENSE in the project root for license information.
-// MUX Reference TwoPaneView.idl, commit c6174f1
+// MUX Reference TwoPaneView.idl, tag winui3/release/1.4.2
 
 namespace Microsoft.UI.Xaml.Controls;