wslsettings: ensure selected setting is auto-expanded and selected (#13689)

* wslsettings: ensure selected setting is auto-selected

Implement keyboard focus management for SettingsExpander controls across settings pages. This resolves an accessibility issue reported internally.

* add asserts

---------

Co-authored-by: Ben Hillis <benhill@ntdev.microsoft.com>

src/windows/wslsettings/Helpers/RuntimeHelper.cs

@@ -1,7 +1,9 @@
 // Copyright (C) Microsoft Corporation. All rights reserved.
 
+using CommunityToolkit.WinUI.Controls;
 using Microsoft.UI.Xaml.Controls;
 using Microsoft.UI.Xaml.Input;
+using System.Diagnostics;
 using System.Reflection;
 using System.Runtime.InteropServices;
 using System.Text;
@@ -47,4 +49,39 @@ public class RuntimeHelper
         FindNextElementOptions fneo = new() { SearchRoot = button.XamlRoot.Content };
         FocusManager.TryMoveFocus(FocusNavigationDirection.Previous, fneo);
     }
+
+    public static void SetupSettingsExpanderFocusManagement(Microsoft.UI.Xaml.FrameworkElement expander, Microsoft.UI.Xaml.Controls.Control firstFocusableElement)
+    {
+        if (expander is CommunityToolkit.WinUI.Controls.SettingsExpander settingsExpander)
+        {
+            settingsExpander.RegisterPropertyChangedCallback(CommunityToolkit.WinUI.Controls.SettingsExpander.IsExpandedProperty, (sender, dp) =>
+            {
+                if (sender is CommunityToolkit.WinUI.Controls.SettingsExpander se && se.IsExpanded)
+                {
+                    System.EventHandler<object>? layoutHandler = null;
+                    layoutHandler = (s, e) =>
+                    {
+                        se.LayoutUpdated -= layoutHandler;
+                        firstFocusableElement.Focus(Microsoft.UI.Xaml.FocusState.Keyboard);
+                    };
+
+                    se.LayoutUpdated += layoutHandler;
+                }
+            });
+        }
+    }
+
+    public static void SetupExpanderFocusManagementByName(Microsoft.UI.Xaml.FrameworkElement parent, string expanderName, string textBoxName)
+    {
+        var expander = parent.FindName(expanderName) as Microsoft.UI.Xaml.FrameworkElement;
+        var textBox = parent.FindName(textBoxName) as Microsoft.UI.Xaml.Controls.Control;
+
+        Debug.Assert(expander != null, $"Expander '{expanderName}' not found");
+        Debug.Assert(textBox != null, $"TextBox '{textBoxName}' not found");
+
+        if (expander != null && textBox != null)
+        {
+            SetupSettingsExpanderFocusManagement(expander, textBox);
+        }
+    }
 }

src/windows/wslsettings/Views/Settings/DeveloperPage.xaml

@@ -25,12 +25,12 @@
                 <ctControls:SettingsCard x:Uid="Settings_HWPerfCounters">
                     <ToggleSwitch x:Uid="Settings_HWPerfCountersToggleSwitch" HorizontalAlignment="Right" MinWidth="0" IsOn="{x:Bind ViewModel.IsOnHWPerfCounters, Mode=TwoWay}"/>
                 </ctControls:SettingsCard>
-                <ctControls:SettingsExpander x:Uid="Settings_CustomKernelPath">
+                <ctControls:SettingsExpander x:Name="CustomKernelPathExpander" x:Uid="Settings_CustomKernelPath">
                     <TextBlock Style="{StaticResource TextBlockFilePathStyle}" Text="{x:Bind ViewModel.CustomKernelPath, Mode=OneWay}"/>
                     <ctControls:SettingsExpander.Items>
                         <ctControls:SettingsCard HorizontalContentAlignment="Left" ContentAlignment="Left" Margin="{StaticResource SettingsExpanderItemMargin}">
                             <StackPanel Orientation="Horizontal">
-                                <TextBox x:Uid="Settings_CustomKernelPathTextBox" Style="{StaticResource TextBoxFilePathStyle}" Margin="{StaticResource InputControlSpacingMargin}"
+                                <TextBox x:Name="CustomKernelPathTextBox" x:Uid="Settings_CustomKernelPathTextBox" Style="{StaticResource TextBoxFilePathStyle}" Margin="{StaticResource InputControlSpacingMargin}"
                                     Text="{x:Bind ViewModel.CustomKernelPath, Mode=TwoWay, UpdateSourceTrigger=LostFocus}"/>
                                 <Button x:Uid="Settings_CustomKernelPathBrowseButton" Style="{StaticResource ButtonSettingStyle}" Margin="{StaticResource InputControlSpacingMargin}"
                                     Click="CustomKernelPath_Click"/>
@@ -38,12 +38,12 @@
                         </ctControls:SettingsCard>
                     </ctControls:SettingsExpander.Items>
                 </ctControls:SettingsExpander>
-                <ctControls:SettingsExpander x:Uid="Settings_CustomKernelModulesPath">
+                <ctControls:SettingsExpander x:Name="CustomKernelModulesPathExpander" x:Uid="Settings_CustomKernelModulesPath">
                     <TextBlock Style="{StaticResource TextBlockFilePathStyle}" Text="{x:Bind ViewModel.CustomKernelModulesPath, Mode=OneWay}"/>
                     <ctControls:SettingsExpander.Items>
                         <ctControls:SettingsCard HorizontalContentAlignment="Left" ContentAlignment="Left" Margin="{StaticResource SettingsExpanderItemMargin}">
                             <StackPanel Orientation="Horizontal">
-                                <TextBox x:Uid="Settings_CustomKernelModulesPathTextBox" Style="{StaticResource TextBoxFilePathStyle}" Margin="{StaticResource InputControlSpacingMargin}"
+                                <TextBox x:Name="CustomKernelModulesPathTextBox" x:Uid="Settings_CustomKernelModulesPathTextBox" Style="{StaticResource TextBoxFilePathStyle}" Margin="{StaticResource InputControlSpacingMargin}"
                                     Text="{x:Bind ViewModel.CustomKernelModulesPath, Mode=TwoWay, UpdateSourceTrigger=LostFocus}"/>
                                 <Button x:Uid="Settings_CustomKernelModulesPathBrowseButton" Style="{StaticResource ButtonSettingStyle}" Margin="{StaticResource InputControlSpacingMargin}"
                                     Click="CustomKernelModulesPath_Click"/>
@@ -51,7 +51,7 @@
                         </ctControls:SettingsCard>
                     </ctControls:SettingsExpander.Items>
                 </ctControls:SettingsExpander>
-                <ctControls:SettingsExpander x:Uid="Settings_CustomSystemDistroPath">
+                <ctControls:SettingsExpander x:Name="CustomSystemDistroPathExpander" x:Uid="Settings_CustomSystemDistroPath">
                     <ctControls:SettingsExpander.Description>
                         <controls:HyperlinkTextBlock x:Uid="Settings_CustomSystemDistroPathDescription"/>
                     </ctControls:SettingsExpander.Description>
@@ -59,7 +59,7 @@
                     <ctControls:SettingsExpander.Items>
                         <ctControls:SettingsCard HorizontalContentAlignment="Left" ContentAlignment="Left" Margin="{StaticResource SettingsExpanderItemMargin}">
                             <StackPanel Orientation="Horizontal">
-                                <TextBox x:Uid="Settings_CustomSystemDistroPathTextBox" Style="{StaticResource TextBoxFilePathStyle}" Margin="{StaticResource InputControlSpacingMargin}"
+                                <TextBox x:Name="CustomSystemDistroPathTextBox" x:Uid="Settings_CustomSystemDistroPathTextBox" Style="{StaticResource TextBoxFilePathStyle}" Margin="{StaticResource InputControlSpacingMargin}"
                                     Text="{x:Bind ViewModel.CustomSystemDistroPath, Mode=TwoWay, UpdateSourceTrigger=LostFocus}"/>
                                 <Button x:Uid="Settings_CustomSystemDistroPathBrowseButton" Style="{StaticResource ButtonSettingStyle}" Margin="{StaticResource InputControlSpacingMargin}"
                                     Click="CustomSystemDistroPath_Click"/>

src/windows/wslsettings/Views/Settings/DeveloperPage.xaml.cs

@@ -27,6 +27,15 @@ public sealed partial class DeveloperPage : Page
                 FrameworkElementAutomationPeer.FromElement(Settings_ErrorTryAgainLater).RaiseAutomationEvent(AutomationEvents.LiveRegionChanged);
             }
         });
+
+        this.Loaded += OnPageLoaded;
+    }
+
+    private void OnPageLoaded(object sender, Microsoft.UI.Xaml.RoutedEventArgs e)
+    {
+        RuntimeHelper.SetupExpanderFocusManagementByName(this, "CustomKernelPathExpander", "CustomKernelPathTextBox");
+        RuntimeHelper.SetupExpanderFocusManagementByName(this, "CustomKernelModulesPathExpander", "CustomKernelModulesPathTextBox");
+        RuntimeHelper.SetupExpanderFocusManagementByName(this, "CustomSystemDistroPathExpander", "CustomSystemDistroPathTextBox");
     }
 
     override protected void OnNavigatedFrom(NavigationEventArgs e)

src/windows/wslsettings/Views/Settings/FileSystemPage.xaml

@@ -18,12 +18,12 @@
         <ScrollViewer Grid.Row="2" VerticalScrollBarVisibility="Auto"
             Visibility="{x:Bind ViewModel.SettingsContentVisibility, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, Converter={StaticResource BooleanToVisibilityConverter}}">
             <StackPanel Spacing="{StaticResource SettingsCardSpacing}">
-                <ctControls:SettingsExpander x:Uid="Settings_DefaultVHDSize">
+                <ctControls:SettingsExpander x:Name="DefaultVHDSizeExpander" x:Uid="Settings_DefaultVHDSize">
                     <TextBlock Style="{StaticResource TextBlockSettingStyle}" Text="{x:Bind ViewModel.DefaultVHDSize, Mode=OneWay, Converter={StaticResource MegabyteStringConverter}}"/>
                     <ctControls:SettingsExpander.Items>
                         <ctControls:SettingsCard HorizontalContentAlignment="Left" ContentAlignment="Left" Margin="{StaticResource SettingsExpanderItemMargin}">
                             <StackPanel Orientation="Horizontal">
-                                <TextBox x:Uid="Settings_DefaultVHDSizeTextBox" Style="{StaticResource TextBoxSettingStyle}" Margin="{StaticResource InputControlSpacingMargin}"
+                                <TextBox x:Name="DefaultVHDSizeTextBox" x:Uid="Settings_DefaultVHDSizeTextBox" Style="{StaticResource TextBoxSettingStyle}" Margin="{StaticResource InputControlSpacingMargin}"
                                     Text="{x:Bind ViewModel.DefaultVHDSize, Mode=TwoWay, UpdateSourceTrigger=LostFocus, Converter={StaticResource MegabyteNumberConverter}}" TextChanged="DefaultVHDSizeTextBox_TextChanged"/>
                                 <Button x:Uid="Settings_DefaultVHDSizeResetButton" Style="{StaticResource ButtonSettingStyle}" Margin="{StaticResource InputControlSpacingMargin}"
                                     Command="{x:Bind ViewModel.DefaultVHDSize_ResetCommand}" IsEnabled="{x:Bind ViewModel.DefaultVHDSize_ResetEnabled, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"

src/windows/wslsettings/Views/Settings/FileSystemPage.xaml.cs

@@ -1,8 +1,10 @@
 // Copyright (C) Microsoft Corporation. All rights reserved.
 
+using CommunityToolkit.WinUI.Controls;
 using Microsoft.UI.Xaml.Automation.Peers;
 using Microsoft.UI.Xaml.Controls;
 using Microsoft.UI.Xaml.Navigation;
+using System.Diagnostics;
 using WslSettings.Contracts.Services;
 using WslSettings.ViewModels.Settings;
 
@@ -26,6 +28,8 @@ public sealed partial class FileSystemPage : Page
                 FrameworkElementAutomationPeer.FromElement(Settings_ErrorTryAgainLater).RaiseAutomationEvent(AutomationEvents.LiveRegionChanged);
             }
         });
+
+        this.Loaded += OnPageLoaded;
     }
 
     override protected void OnNavigatedFrom(NavigationEventArgs e)
@@ -53,4 +57,18 @@ public sealed partial class FileSystemPage : Page
         TextBox? textBox = sender as TextBox;
         ViewModel.SetDefaultVHDSize_ResetEnabled(textBox!.Text);
     }
+
+    private void OnPageLoaded(object sender, Microsoft.UI.Xaml.RoutedEventArgs e)
+    {
+        var expander = this.FindName("DefaultVHDSizeExpander") as SettingsExpander;
+        var textBox = this.FindName("DefaultVHDSizeTextBox") as TextBox;
+
+        Debug.Assert(expander != null, "DefaultVHDSizeExpander not found");
+        Debug.Assert(textBox != null, "DefaultVHDSizeTextBox not found");
+
+        if (expander != null && textBox != null)
+        {
+            RuntimeHelper.SetupSettingsExpanderFocusManagement(expander, textBox);
+        }
+    }
 }

src/windows/wslsettings/Views/Settings/MemAndProcPage.xaml

@@ -18,12 +18,12 @@
         <ScrollViewer Grid.Row="2" VerticalScrollBarVisibility="Auto"
             Visibility="{x:Bind ViewModel.SettingsContentVisibility, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, Converter={StaticResource BooleanToVisibilityConverter}}">
             <StackPanel Spacing="{StaticResource SettingsCardSpacing}">
-                <ctControls:SettingsExpander x:Uid="Settings_ProcCount">
+                <ctControls:SettingsExpander x:Name="ProcCountExpander" x:Uid="Settings_ProcCount">
                     <TextBlock Style="{StaticResource TextBlockSettingStyle}" Text="{x:Bind ViewModel.ProcCount, Mode=OneWay}"/>
                     <ctControls:SettingsExpander.Items>
                         <ctControls:SettingsCard HorizontalContentAlignment="Left" ContentAlignment="Left" Margin="{StaticResource SettingsExpanderItemMargin}">
                             <StackPanel Orientation="Horizontal">
-                                <TextBox x:Uid="Settings_ProcCountTextBox" Style="{StaticResource TextBoxSettingStyle}" Margin="{StaticResource InputControlSpacingMargin}"
+                                <TextBox x:Name="ProcCountTextBox" x:Uid="Settings_ProcCountTextBox" Style="{StaticResource TextBoxSettingStyle}" Margin="{StaticResource InputControlSpacingMargin}"
                                     Text="{x:Bind ViewModel.ProcCount, Mode=TwoWay, UpdateSourceTrigger=LostFocus}" TextChanged="ProcCountTextBox_TextChanged"/>
                                 <Button x:Uid="Settings_ProcCountResetButton" Style="{StaticResource ButtonSettingStyle}" Margin="{StaticResource InputControlSpacingMargin}"
                                     Command="{x:Bind ViewModel.ProcCount_ResetCommand}" IsEnabled="{x:Bind ViewModel.ProcCount_ResetEnabled, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
@@ -32,12 +32,12 @@
                         </ctControls:SettingsCard>
                     </ctControls:SettingsExpander.Items>
                 </ctControls:SettingsExpander>
-                <ctControls:SettingsExpander x:Uid="Settings_MemorySize">
+                <ctControls:SettingsExpander x:Name="MemorySizeExpander" x:Uid="Settings_MemorySize">
                     <TextBlock Style="{StaticResource TextBlockSettingStyle}" Text="{x:Bind ViewModel.MemorySize, Mode=OneWay, Converter={StaticResource MegabyteStringConverter}}"/>
                     <ctControls:SettingsExpander.Items>
                         <ctControls:SettingsCard HorizontalContentAlignment="Left" ContentAlignment="Left" Margin="{StaticResource SettingsExpanderItemMargin}">
                             <StackPanel Orientation="Horizontal">
-                                <TextBox x:Uid="Settings_MemorySizeTextBox" Style="{StaticResource TextBoxSettingStyle}" Margin="{StaticResource InputControlSpacingMargin}"
+                                <TextBox x:Name="MemorySizeTextBox" x:Uid="Settings_MemorySizeTextBox" Style="{StaticResource TextBoxSettingStyle}" Margin="{StaticResource InputControlSpacingMargin}"
                                     Text="{x:Bind ViewModel.MemorySize, Mode=TwoWay, UpdateSourceTrigger=LostFocus, Converter={StaticResource MegabyteNumberConverter}}" TextChanged="MemorySizeTextBox_TextChanged"/>
                                 <Button x:Uid="Settings_MemorySizeResetButton" Style="{StaticResource ButtonSettingStyle}" Margin="{StaticResource InputControlSpacingMargin}"
                                     Command="{x:Bind ViewModel.MemorySize_ResetCommand}" IsEnabled="{x:Bind ViewModel.MemorySize_ResetEnabled, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
@@ -46,12 +46,12 @@
                         </ctControls:SettingsCard>
                     </ctControls:SettingsExpander.Items>
                 </ctControls:SettingsExpander>
-                <ctControls:SettingsExpander x:Uid="Settings_SwapSize">
+                <ctControls:SettingsExpander x:Name="SwapSizeExpander" x:Uid="Settings_SwapSize">
                     <TextBlock Style="{StaticResource TextBlockSettingStyle}" Text="{x:Bind ViewModel.SwapSize, Mode=OneWay, Converter={StaticResource MegabyteStringConverter}}"/>
                     <ctControls:SettingsExpander.Items>
                         <ctControls:SettingsCard HorizontalContentAlignment="Left" ContentAlignment="Left" Margin="{StaticResource SettingsExpanderItemMargin}">
                             <StackPanel Orientation="Horizontal">
-                                <TextBox x:Uid="Settings_SwapSizeTextBox" Style="{StaticResource TextBoxSettingStyle}" Margin="{StaticResource InputControlSpacingMargin}"
+                                <TextBox x:Name="SwapSizeTextBox" x:Uid="Settings_SwapSizeTextBox" Style="{StaticResource TextBoxSettingStyle}" Margin="{StaticResource InputControlSpacingMargin}"
                                     Text="{x:Bind ViewModel.SwapSize, Mode=TwoWay, UpdateSourceTrigger=LostFocus, Converter={StaticResource MegabyteNumberConverter}}" TextChanged="SwapSizeTextBox_TextChanged"/>
                                 <Button x:Uid="Settings_SwapSizeResetButton" Style="{StaticResource ButtonSettingStyle}" Margin="{StaticResource InputControlSpacingMargin}"
                                     Command="{x:Bind ViewModel.SwapSize_ResetCommand}" IsEnabled="{x:Bind ViewModel.SwapSize_ResetEnabled, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
@@ -60,12 +60,12 @@
                         </ctControls:SettingsCard>
                     </ctControls:SettingsExpander.Items>
                 </ctControls:SettingsExpander>
-                <ctControls:SettingsExpander x:Uid="Settings_SwapFilePath">
+                <ctControls:SettingsExpander x:Name="SwapFilePathExpander" x:Uid="Settings_SwapFilePath">
                     <TextBlock Style="{StaticResource TextBlockFilePathStyle}" Text="{x:Bind ViewModel.SwapFilePath, Mode=OneWay}"/>
                     <ctControls:SettingsExpander.Items>
                         <ctControls:SettingsCard HorizontalContentAlignment="Left" ContentAlignment="Left" Margin="{StaticResource SettingsExpanderItemMargin}">
                             <StackPanel Orientation="Horizontal">
-                                <TextBox x:Uid="Settings_SwapFilePathTextBox" Style="{StaticResource TextBoxFilePathStyle}" Margin="{StaticResource InputControlSpacingMargin}"
+                                <TextBox x:Name="SwapFilePathTextBox" x:Uid="Settings_SwapFilePathTextBox" Style="{StaticResource TextBoxFilePathStyle}" Margin="{StaticResource InputControlSpacingMargin}"
                                     Text="{x:Bind ViewModel.SwapFilePath, Mode=TwoWay, UpdateSourceTrigger=LostFocus}"/>
                                 <Button x:Uid="Settings_SwapFilePathBrowseButton" Style="{StaticResource ButtonSettingStyle}" Margin="{StaticResource InputControlSpacingMargin}"
                                     Click="SwapFilePath_Click"/>

src/windows/wslsettings/Views/Settings/MemAndProcPage.xaml.cs

@@ -27,6 +27,16 @@ public sealed partial class MemAndProcPage : Page
                 FrameworkElementAutomationPeer.FromElement(Settings_ErrorTryAgainLater).RaiseAutomationEvent(AutomationEvents.LiveRegionChanged);
             }
         });
+
+        this.Loaded += OnPageLoaded;
+    }
+
+    private void OnPageLoaded(object sender, Microsoft.UI.Xaml.RoutedEventArgs e)
+    {
+        RuntimeHelper.SetupExpanderFocusManagementByName(this, "ProcCountExpander", "ProcCountTextBox");
+        RuntimeHelper.SetupExpanderFocusManagementByName(this, "MemorySizeExpander", "MemorySizeTextBox");
+        RuntimeHelper.SetupExpanderFocusManagementByName(this, "SwapSizeExpander", "SwapSizeTextBox");
+        RuntimeHelper.SetupExpanderFocusManagementByName(this, "SwapFilePathExpander", "SwapFilePathTextBox");
     }
 
     override protected void OnNavigatedFrom(NavigationEventArgs e)

src/windows/wslsettings/Views/Settings/NetworkingPage.xaml

@@ -25,12 +25,12 @@
                 <ctControls:SettingsCard x:Uid="Settings_HyperVFirewall">
                     <ToggleSwitch x:Uid="Settings_HyperVFirewallToggleSwitch" HorizontalAlignment="Right" MinWidth="0" IsOn="{x:Bind ViewModel.IsOnHyperVFirewall, Mode=TwoWay}"/>
                 </ctControls:SettingsCard>
-                <ctControls:SettingsExpander x:Uid="Settings_IgnoredPorts">
+                <ctControls:SettingsExpander x:Name="IgnoredPortsExpander" x:Uid="Settings_IgnoredPorts">
                     <TextBlock Style="{StaticResource TextBlockSettingStyle}" Text="{x:Bind ViewModel.IgnoredPorts, Mode=OneWay}"/>
                     <ctControls:SettingsExpander.Items>
                         <ctControls:SettingsCard HorizontalContentAlignment="Left" ContentAlignment="Left" Margin="{StaticResource SettingsExpanderItemMargin}">
                             <StackPanel Orientation="Horizontal">
-                                <TextBox x:Uid="Settings_IgnoredPortsTextBox" Style="{StaticResource TextBoxSettingStyle}" Margin="{StaticResource InputControlSpacingMargin}"
+                                <TextBox x:Name="IgnoredPortsTextBox" x:Uid="Settings_IgnoredPortsTextBox" Style="{StaticResource TextBoxSettingStyle}" Margin="{StaticResource InputControlSpacingMargin}"
                                     Text="{x:Bind ViewModel.IgnoredPorts, Mode=TwoWay, UpdateSourceTrigger=LostFocus}"/>
                                 <Button x:Uid="Settings_IgnoredPortsResetButton" Style="{StaticResource ButtonSettingStyle}" Margin="{StaticResource InputControlSpacingMargin}"
                                     Command="{x:Bind ViewModel.IgnoredPorts_ResetCommand}" IsEnabled="{x:Bind ViewModel.IgnoredPorts_ResetEnabled, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
@@ -48,12 +48,12 @@
                 <ctControls:SettingsCard x:Uid="Settings_AutoProxy">
                     <ToggleSwitch x:Uid="Settings_AutoProxyToggleSwitch" HorizontalAlignment="Right" MinWidth="0" IsOn="{x:Bind ViewModel.IsOnAutoProxy, Mode=TwoWay}"/>
                 </ctControls:SettingsCard>
-                <ctControls:SettingsExpander x:Uid="Settings_InitialAutoProxyTimeout">
+                <ctControls:SettingsExpander x:Name="InitialAutoProxyTimeoutExpander" x:Uid="Settings_InitialAutoProxyTimeout">
                     <TextBlock Style="{StaticResource TextBlockSettingStyle}" Text="{x:Bind ViewModel.InitialAutoProxyTimeout, Mode=OneWay, Converter={StaticResource MillisecondsStringConverter}}"/>
                     <ctControls:SettingsExpander.Items>
                         <ctControls:SettingsCard HorizontalContentAlignment="Left" ContentAlignment="Left" Margin="{StaticResource SettingsExpanderItemMargin}">
                             <StackPanel Orientation="Horizontal">
-                                <TextBox x:Uid="Settings_InitialAutoProxyTimeoutTextBox" Style="{StaticResource TextBoxSettingStyle}" Margin="{StaticResource InputControlSpacingMargin}"
+                                <TextBox x:Name="InitialAutoProxyTimeoutTextBox" x:Uid="Settings_InitialAutoProxyTimeoutTextBox" Style="{StaticResource TextBoxSettingStyle}" Margin="{StaticResource InputControlSpacingMargin}"
                                     Text="{x:Bind ViewModel.InitialAutoProxyTimeout, Mode=TwoWay, UpdateSourceTrigger=LostFocus}" TextChanged="InitialAutoProxyTimeoutTextBox_TextChanged"/>
                                 <Button x:Uid="Settings_InitialAutoProxyTimeoutResetButton" Style="{StaticResource ButtonSettingStyle}" Margin="{StaticResource InputControlSpacingMargin}"
                                     Command="{x:Bind ViewModel.InitialAutoProxyTimeout_ResetCommand}" IsEnabled="{x:Bind ViewModel.InitialAutoProxyTimeout_ResetEnabled, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"

src/windows/wslsettings/Views/Settings/NetworkingPage.xaml.cs

@@ -26,6 +26,14 @@ public sealed partial class NetworkingPage : Page
                 FrameworkElementAutomationPeer.FromElement(Settings_ErrorTryAgainLater).RaiseAutomationEvent(AutomationEvents.LiveRegionChanged);
             }
         });
+
+        this.Loaded += OnPageLoaded;
+    }
+
+    private void OnPageLoaded(object sender, Microsoft.UI.Xaml.RoutedEventArgs e)
+    {
+        RuntimeHelper.SetupExpanderFocusManagementByName(this, "IgnoredPortsExpander", "IgnoredPortsTextBox");
+        RuntimeHelper.SetupExpanderFocusManagementByName(this, "InitialAutoProxyTimeoutExpander", "InitialAutoProxyTimeoutTextBox");
     }
 
     override protected void OnNavigatedFrom(NavigationEventArgs e)

src/windows/wslsettings/Views/Settings/OptionalFeaturesPage.xaml

@@ -38,12 +38,12 @@
                 <ctControls:SettingsCard x:Uid="Settings_SparseVHD">
                     <ToggleSwitch x:Uid="Settings_SparseVHDToggleSwitch" HorizontalAlignment="Right" MinWidth="0" IsOn="{x:Bind ViewModel.IsOnSparseVHD, Mode=TwoWay}"/>
                 </ctControls:SettingsCard>
-                <ctControls:SettingsExpander x:Uid="Settings_VMIdleTimeout">
+                <ctControls:SettingsExpander x:Name="VMIdleTimeoutExpander" x:Uid="Settings_VMIdleTimeout">
                     <TextBlock Style="{StaticResource TextBlockSettingStyle}" Text="{x:Bind ViewModel.VMIdleTimeout, Mode=OneWay, Converter={StaticResource MillisecondsStringConverter}}"/>
                     <ctControls:SettingsExpander.Items>
                         <ctControls:SettingsCard HorizontalContentAlignment="Left" ContentAlignment="Left" Margin="{StaticResource SettingsExpanderItemMargin}">
                             <StackPanel Orientation="Horizontal">
-                                <TextBox x:Uid="Settings_VMIdleTimeoutTextBox" Style="{StaticResource TextBoxFilePathStyle}" Margin="{StaticResource InputControlSpacingMargin}"
+                                <TextBox x:Name="VMIdleTimeoutTextBox" x:Uid="Settings_VMIdleTimeoutTextBox" Style="{StaticResource TextBoxFilePathStyle}" Margin="{StaticResource InputControlSpacingMargin}"
                                     Text="{x:Bind ViewModel.VMIdleTimeout, Mode=TwoWay, UpdateSourceTrigger=LostFocus}" TextChanged="VMIdleTimeoutTextBox_TextChanged"/>
                                 <Button x:Uid="Settings_VMIdleTimeoutResetButton" Style="{StaticResource ButtonSettingStyle}" Margin="{StaticResource InputControlSpacingMargin}"
                                     Command="{x:Bind ViewModel.VMIdleTimeout_ResetCommand}" IsEnabled="{x:Bind ViewModel.VMIdleTimeout_ResetEnabled, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"

src/windows/wslsettings/Views/Settings/OptionalFeaturesPage.xaml.cs

@@ -26,6 +26,14 @@ public sealed partial class OptionalFeaturesPage : Page
                 FrameworkElementAutomationPeer.FromElement(Settings_ErrorTryAgainLater).RaiseAutomationEvent(AutomationEvents.LiveRegionChanged);
             }
         });
+
+        this.Loaded += OnPageLoaded;
+    }
+
+    private void OnPageLoaded(object sender, Microsoft.UI.Xaml.RoutedEventArgs e)
+    {
+        RuntimeHelper.SetupExpanderFocusManagementByName(this, "SystemdSettingsExpander", "InitTextBox");
+        RuntimeHelper.SetupExpanderFocusManagementByName(this, "VMIdleTimeoutExpander", "VMIdleTimeoutTextBox");
     }
 
     override protected void OnNavigatedFrom(NavigationEventArgs e)