diff --git a/UITests/UITests.App/DefaultPage.xaml b/UITests/UITests.App/DefaultPage.xaml
new file mode 100644
index 00000000000..9796cadd1a1
--- /dev/null
+++ b/UITests/UITests.App/DefaultPage.xaml
@@ -0,0 +1,13 @@
+<Page
+    x:Class="UITests.App.DefaultPage"
+    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+    mc:Ignorable="d"
+    Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
+
+    <Grid>
+
+    </Grid>
+</Page>
diff --git a/UITests/UITests.App/DefaultPage.xaml.cs b/UITests/UITests.App/DefaultPage.xaml.cs
new file mode 100644
index 00000000000..c5fa57ae8f4
--- /dev/null
+++ b/UITests/UITests.App/DefaultPage.xaml.cs
@@ -0,0 +1,19 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using Windows.UI.Xaml.Controls;
+
+namespace UITests.App
+{
+    /// <summary>
+    /// An empty page that can be used on its own or navigated to within a Frame.
+    /// </summary>
+    public sealed partial class DefaultPage : Page
+    {
+        public DefaultPage()
+        {
+            this.InitializeComponent();
+        }
+    }
+}
diff --git a/UITests/UITests.App/MainPage.xaml b/UITests/UITests.App/MainPage.xaml
index d38db07e3e3..098a892077c 100644
--- a/UITests/UITests.App/MainPage.xaml
+++ b/UITests/UITests.App/MainPage.xaml
@@ -6,14 +6,11 @@
     xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
     xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
     mc:Ignorable="d"
+    Loaded="Page_Loaded"
     Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
 
     <Grid>
         <testhelpers:TestAutomationHelpersPanel />
-
-        <StackPanel HorizontalAlignment="Center" VerticalAlignment="Center">
-            <Button Content="Click Me" Click="Button_Click"/>
-            <TextBlock x:Name="textBlock"/>
-        </StackPanel>
+        <Frame x:Name="navigationFrame" />
     </Grid>
 </Page>
diff --git a/UITests/UITests.App/MainPage.xaml.cs b/UITests/UITests.App/MainPage.xaml.cs
index b44c1291f46..d3a3821ea42 100644
--- a/UITests/UITests.App/MainPage.xaml.cs
+++ b/UITests/UITests.App/MainPage.xaml.cs
@@ -2,18 +2,79 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+using System;
+using System.IO;
+using System.Net;
+using System.Net.Sockets;
+using System.Threading;
+using System.Threading.Tasks;
+using Windows.UI.Core;
+using Windows.UI.Xaml;
+
 namespace UITests.App
 {
     public sealed partial class MainPage
     {
+        private static readonly string _pageNS = typeof(MainPage).Namespace + ".Pages.";
+        private NetworkStream clientStream;
+        private StreamWriter writer;
+
         public MainPage()
         {
             InitializeComponent();
         }
 
-        private void Button_Click(object sender, Windows.UI.Xaml.RoutedEventArgs e)
+        private void Page_Loaded(object sender, RoutedEventArgs e)
         {
-            textBlock.Text = "Clicked";
+            navigationFrame.Navigate(typeof(DefaultPage));
+
+            Task.Run(ConnectToTestDriver);
+        }
+
+        private void ConnectToTestDriver()
+        {
+            var client = new TcpClient();
+            client.ConnectAsync(IPAddress.Loopback, 13000);
+
+            clientStream = client.GetStream();
+            writer = new StreamWriter(clientStream)
+            {
+                AutoFlush = true
+            };
+
+            writer.WriteLine("Ready");
+
+            var thread = new Thread(new ThreadStart(ListenForPageRequest));
+            thread.Start();
+        }
+
+        private void ListenForPageRequest()
+        {
+            var reader = new StreamReader(clientStream);
+
+            while (true)
+            {
+                try
+                {
+                    if (reader.ReadLine() is string request)
+                    {
+                        var type = Type.GetType(_pageNS + request);
+                        Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () => navigationFrame.Navigate(type))
+                            .AsTask()
+                            .ContinueWith(_ => writer.WriteLine("Opened " + request));
+                    }
+                    else
+                    {
+                        // The server has disconnected
+                        break;
+                    }
+                }
+                catch
+                {
+                    // A socket error has occurred
+                    break;
+                }
+            }
         }
     }
 }
diff --git a/UITests/UITests.App/Package.appxmanifest b/UITests/UITests.App/Package.appxmanifest
index a17d7b8e653..6e55a84ad3d 100644
--- a/UITests/UITests.App/Package.appxmanifest
+++ b/UITests/UITests.App/Package.appxmanifest
@@ -45,5 +45,6 @@
 
   <Capabilities>
     <Capability Name="internetClient" />
+    <Capability Name="privateNetworkClientServer"/>
   </Capabilities>
 </Package>
\ No newline at end of file
diff --git a/UITests/UITests.App/Pages/Controls/TextBoxMaskTestPage.xaml b/UITests/UITests.App/Pages/Controls/TextBoxMaskTestPage.xaml
new file mode 100644
index 00000000000..96ce0c21194
--- /dev/null
+++ b/UITests/UITests.App/Pages/Controls/TextBoxMaskTestPage.xaml
@@ -0,0 +1,51 @@
+<Page
+    x:Class="UITests.App.Pages.TextBoxMaskTestPage"
+    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+    xmlns:extensions="using:Microsoft.Toolkit.Uwp.UI.Extensions"
+    mc:Ignorable="d"
+    Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
+    <Grid HorizontalAlignment="Center" VerticalAlignment="Center">
+        <Grid.RowDefinitions>
+            <RowDefinition Height="Auto"/>
+            <RowDefinition Height="10"/>
+            <RowDefinition Height="Auto"/>
+        </Grid.RowDefinitions>
+        <Grid.ColumnDefinitions>
+            <ColumnDefinition Width="Auto"/>
+            <ColumnDefinition Width="10"/>
+            <ColumnDefinition Width="Auto"/>
+        </Grid.ColumnDefinitions>
+        <Button 
+            x:Name="ChangeButton" 
+            Content="Change Target Value"
+            Click="ChangeButton_Click"
+            Grid.Column="0" Grid.Row="0"
+            />
+        <TextBox 
+            x:Name="TextBox"
+            Width="120"
+	        Padding="0,4,0,0"
+            VerticalAlignment="Center"
+            extensions:TextBoxMask.CustomMask="5:[0-5]"
+            extensions:TextBoxMask.Mask="99:59:59"
+            TextAlignment="Center"
+            Text="{x:Bind Value, Mode=OneWay}"
+            Grid.Column="2" Grid.Row="0"
+            />
+        <TextBlock 
+            x:Name="InitialValueTextBlock"
+            Text="{x:Bind InitialValue}"
+            HorizontalAlignment="Center"
+            Grid.Column="0" Grid.Row="2"
+            />
+        <TextBlock
+            x:Name="NewValueTextBlock"
+            Text="{x:Bind NewValue}"
+            HorizontalAlignment="Center"
+            Grid.Column="2" Grid.Row="2"
+            />
+    </Grid>
+</Page>
diff --git a/UITests/UITests.App/Pages/Controls/TextBoxMaskTestPage.xaml.cs b/UITests/UITests.App/Pages/Controls/TextBoxMaskTestPage.xaml.cs
new file mode 100644
index 00000000000..f872d27017e
--- /dev/null
+++ b/UITests/UITests.App/Pages/Controls/TextBoxMaskTestPage.xaml.cs
@@ -0,0 +1,41 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using Windows.UI.Xaml;
+using Windows.UI.Xaml.Controls;
+
+namespace UITests.App.Pages
+{
+    /// <summary>
+    /// An empty page that can be used on its own or navigated to within a Frame.
+    /// </summary>
+    public sealed partial class TextBoxMaskTestPage : Page
+    {
+        private const string INITIAL_VALUE = "12:50:59";
+        private const string NEW_VALUE = "00:00:00";
+
+        public string InitialValue => INITIAL_VALUE;
+
+        public string NewValue => NEW_VALUE;
+
+        public string Value
+        {
+            get { return (string)GetValue(ValueProperty); }
+            set { SetValue(ValueProperty, value); }
+        }
+
+        public static readonly DependencyProperty ValueProperty =
+            DependencyProperty.Register(nameof(Value), typeof(string), typeof(TextBoxMaskTestPage), new PropertyMetadata(INITIAL_VALUE));
+
+        public TextBoxMaskTestPage()
+        {
+            this.InitializeComponent();
+        }
+
+        private void ChangeButton_Click(object sender, RoutedEventArgs e)
+        {
+            Value = NEW_VALUE;
+        }
+    }
+}
diff --git a/UITests/UITests.App/Pages/SimpleTest.xaml b/UITests/UITests.App/Pages/SimpleTest.xaml
new file mode 100644
index 00000000000..1ab5d6484bc
--- /dev/null
+++ b/UITests/UITests.App/Pages/SimpleTest.xaml
@@ -0,0 +1,13 @@
+<Page
+    x:Class="UITests.App.Pages.SimpleTest"
+    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+    mc:Ignorable="d"
+    Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
+    <StackPanel HorizontalAlignment="Center" VerticalAlignment="Center">
+        <Button Content="Click Me" Click="Button_Click"/>
+        <TextBlock x:Name="textBlock"/>
+    </StackPanel>
+</Page>
diff --git a/UITests/UITests.App/Pages/SimpleTest.xaml.cs b/UITests/UITests.App/Pages/SimpleTest.xaml.cs
new file mode 100644
index 00000000000..db474735c36
--- /dev/null
+++ b/UITests/UITests.App/Pages/SimpleTest.xaml.cs
@@ -0,0 +1,25 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using Windows.UI.Xaml;
+using Windows.UI.Xaml.Controls;
+
+namespace UITests.App.Pages
+{
+    /// <summary>
+    /// An empty page that can be used on its own or navigated to within a Frame.
+    /// </summary>
+    public sealed partial class SimpleTest : Page
+    {
+        public SimpleTest()
+        {
+            this.InitializeComponent();
+        }
+
+        private void Button_Click(object sender, RoutedEventArgs e)
+        {
+            textBlock.Text = "Clicked";
+        }
+    }
+}
diff --git a/UITests/UITests.App/UITests.App.csproj b/UITests/UITests.App/UITests.App.csproj
index 48fc8de5936..b11634a50c2 100644
--- a/UITests/UITests.App/UITests.App.csproj
+++ b/UITests/UITests.App/UITests.App.csproj
@@ -40,6 +40,7 @@
     <UseVSHostingProcess>false</UseVSHostingProcess>
     <ErrorReport>prompt</ErrorReport>
     <Prefer32Bit>true</Prefer32Bit>
+    <LangVersion>8.0</LangVersion>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Release|x86'">
     <OutputPath>bin\x86\Release\</OutputPath>
@@ -52,6 +53,7 @@
     <ErrorReport>prompt</ErrorReport>
     <Prefer32Bit>true</Prefer32Bit>
     <UseDotNetNativeToolchain>true</UseDotNetNativeToolchain>
+    <LangVersion>8.0</LangVersion>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Debug|ARM'">
     <DebugSymbols>true</DebugSymbols>
@@ -63,6 +65,7 @@
     <UseVSHostingProcess>false</UseVSHostingProcess>
     <ErrorReport>prompt</ErrorReport>
     <Prefer32Bit>true</Prefer32Bit>
+    <LangVersion>8.0</LangVersion>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Release|ARM'">
     <OutputPath>bin\ARM\Release\</OutputPath>
@@ -75,6 +78,7 @@
     <ErrorReport>prompt</ErrorReport>
     <Prefer32Bit>true</Prefer32Bit>
     <UseDotNetNativeToolchain>true</UseDotNetNativeToolchain>
+    <LangVersion>8.0</LangVersion>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Debug|ARM64'">
     <DebugSymbols>true</DebugSymbols>
@@ -87,6 +91,7 @@
     <ErrorReport>prompt</ErrorReport>
     <Prefer32Bit>true</Prefer32Bit>
     <UseDotNetNativeToolchain>true</UseDotNetNativeToolchain>
+    <LangVersion>8.0</LangVersion>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Release|ARM64'">
     <OutputPath>bin\ARM64\Release\</OutputPath>
@@ -99,6 +104,7 @@
     <ErrorReport>prompt</ErrorReport>
     <Prefer32Bit>true</Prefer32Bit>
     <UseDotNetNativeToolchain>true</UseDotNetNativeToolchain>
+    <LangVersion>8.0</LangVersion>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Debug|x64'">
     <DebugSymbols>true</DebugSymbols>
@@ -110,6 +116,7 @@
     <UseVSHostingProcess>false</UseVSHostingProcess>
     <ErrorReport>prompt</ErrorReport>
     <Prefer32Bit>true</Prefer32Bit>
+    <LangVersion>8.0</LangVersion>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Release|x64'">
     <OutputPath>bin\x64\Release\</OutputPath>
@@ -122,6 +129,7 @@
     <ErrorReport>prompt</ErrorReport>
     <Prefer32Bit>true</Prefer32Bit>
     <UseDotNetNativeToolchain>true</UseDotNetNativeToolchain>
+    <LangVersion>8.0</LangVersion>
   </PropertyGroup>
   <PropertyGroup>
     <RestoreProjectStyle>PackageReference</RestoreProjectStyle>
@@ -130,9 +138,18 @@
     <Compile Include="App.xaml.cs">
       <DependentUpon>App.xaml</DependentUpon>
     </Compile>
+    <Compile Include="DefaultPage.xaml.cs">
+      <DependentUpon>DefaultPage.xaml</DependentUpon>
+    </Compile>
     <Compile Include="MainPage.xaml.cs">
       <DependentUpon>MainPage.xaml</DependentUpon>
     </Compile>
+    <Compile Include="Pages\SimpleTest.xaml.cs">
+      <DependentUpon>SimpleTest.xaml</DependentUpon>
+    </Compile>
+    <Compile Include="Pages\Controls\TextBoxMaskTestPage.xaml.cs">
+      <DependentUpon>TextBoxMaskTestPage.xaml</DependentUpon>
+    </Compile>
     <Compile Include="Properties\AssemblyInfo.cs" />
   </ItemGroup>
   <ItemGroup>
@@ -155,10 +172,22 @@
       <Generator>MSBuild:Compile</Generator>
       <SubType>Designer</SubType>
     </ApplicationDefinition>
+    <Page Include="DefaultPage.xaml">
+      <Generator>MSBuild:Compile</Generator>
+      <SubType>Designer</SubType>
+    </Page>
     <Page Include="MainPage.xaml">
       <Generator>MSBuild:Compile</Generator>
       <SubType>Designer</SubType>
     </Page>
+    <Page Include="Pages\SimpleTest.xaml">
+      <SubType>Designer</SubType>
+      <Generator>MSBuild:Compile</Generator>
+    </Page>
+    <Page Include="Pages\Controls\TextBoxMaskTestPage.xaml">
+      <SubType>Designer</SubType>
+      <Generator>MSBuild:Compile</Generator>
+    </Page>
   </ItemGroup>
   <ItemGroup>
     <PackageReference Include="Microsoft.NETCore.UniversalWindowsPlatform">
@@ -252,4 +281,4 @@
   <Target Name="AfterBuild">
   </Target>
   -->
-</Project>
+</Project>
\ No newline at end of file
diff --git a/UITests/UITests.Tests.Shared/Tests.cs b/UITests/UITests.Tests.Shared/Tests.cs
index bba017d8c9e..56cee816924 100644
--- a/UITests/UITests.Tests.Shared/Tests.cs
+++ b/UITests/UITests.Tests.Shared/Tests.cs
@@ -5,6 +5,8 @@
 using System;
 using System.IO;
 using System.Linq;
+using System.Net;
+using System.Net.Sockets;
 using System.Reflection;
 using Microsoft.Windows.Apps.Test.Foundation.Controls;
 using Windows.UI.Xaml.Tests.MUXControls.InteractionTests.Common;
@@ -23,6 +25,9 @@ namespace UITests.Tests
     [TestClass]
     public class Tests
     {
+        private static StreamReader _streamReader;
+        private static StreamWriter _streamWriter;
+
         public static TestApplicationInfo WinUICsUWPSampleApp
         {
             get
@@ -83,7 +88,18 @@ public static TestSetupHelper.TestSetupHelperOptions TestSetupHelperOptions
         [TestProperty("Platform", "Any")]
         public static void ClassInitialize(TestContext testContext)
         {
+            var listener = new TcpListener(IPAddress.Loopback, 13000);
+            listener.Start();
+
             TestEnvironment.Initialize(testContext, WinUICsUWPSampleApp);
+
+            var client = listener.AcceptTcpClient();
+
+            var stream = client.GetStream();
+            _streamReader = new StreamReader(stream);
+            _streamWriter = new StreamWriter(stream);
+
+            Verify.AreEqual("Ready", _streamReader.ReadLine());
         }
 
         [ClassCleanup]
@@ -98,8 +114,10 @@ public void TestCleanup()
         }
 
         [TestMethod]
-        public void SimpleLaunchTest()
+        public void SimpleTest()
         {
+            Verify.IsTrue(OpenTest("SimpleTest"));
+
             var button = new Button(FindElement.ByName("Click Me"));
             var textBlock = new TextBlock(FindElement.ById("textBlock"));
 
@@ -113,5 +131,32 @@ public void SimpleLaunchTest()
 
             Verify.AreEqual("Clicked", textBlock.GetText());
         }
+
+        [TestMethod]
+        public void TestTextBoxMaskBinding_Property()
+        {
+            Verify.IsTrue(OpenTest("TextBoxMaskTestPage"));
+
+            var initialValue = FindElement.ById<TextBlock>("InitialValueTextBlock").GetText();
+            var textBox = FindElement.ById<Edit>("TextBox");
+
+            Verify.AreEqual(initialValue, textBox.GetText());
+
+            var changeButton = FindElement.ById<Button>("ChangeButton");
+
+            changeButton.Click();
+            Wait.ForIdle();
+
+            var newValue = FindElement.ById<TextBlock>("NewValueTextBlock").GetText();
+
+            Verify.AreEqual(newValue, textBox.GetText());
+        }
+
+        private static bool OpenTest(string name)
+        {
+            _streamWriter.WriteLine(name);
+            _streamWriter.Flush();
+            return _streamReader.ReadLine() == "Opened " + name;
+        }
     }
 }
\ No newline at end of file
diff --git a/azure-pipelines.yml b/azure-pipelines.yml
index 75d381267ec..f5032bca46e 100644
--- a/azure-pipelines.yml
+++ b/azure-pipelines.yml
@@ -39,6 +39,9 @@ jobs:
   - script: nbgv cloud
     displayName: Set Version
 
+  - powershell: 'CheckNetIsolation.exe LoopbackExempt -a -n=3568ebdf-5b6b-4ddd-bb17-462d614ba50f_gspb8g6x97k2t'
+    displayName: Enable Test networking
+
   #- powershell: .\build\Install-WindowsSdkISO.ps1 19041
   #  displayName: Insider SDK