Address more review feedback.

src/Microsoft.VisualBasic.Forms/src/Microsoft/VisualBasic/ApplicationServices/WindowsFormsApplicationBase.vb

@@ -832,6 +832,9 @@ Namespace Microsoft.VisualBasic.ApplicationServices
         ''' <summary>
         '''  Gets or sets the VisualStylesMode for the Application.
         ''' </summary>
+        ''' <returns>
+        '''  The <see cref="VisualStylesMode"/> that the application is running in.
+        ''' </returns>
         <Experimental(DiagnosticIDs.ExperimentalVisualStyles)>
         <EditorBrowsable(EditorBrowsableState.Never)>
         Protected Property VisualStylesMode As VisualStylesMode
@@ -846,6 +849,9 @@ Namespace Microsoft.VisualBasic.ApplicationServices
         ''' <summary>
         '''  Gets or sets the ColorMode for the Application.
         ''' </summary>
+        ''' <returns>
+        '''  The <see cref="SystemColorMode"/> that the application is running in.
+        ''' </returns>
         <Experimental(DiagnosticIDs.ExperimentalDarkMode)>
         <EditorBrowsable(EditorBrowsableState.Never)>
         Protected Property ColorMode As SystemColorMode

src/System.Windows.Forms.Analyzers.CodeFixes.CSharp/Resources/SR.resx

@@ -120,4 +120,4 @@
   <data name="AddDesignerSerializationVisibilityCodeFixTitle" xml:space="preserve">
     <value>Add DesignerSerializationVisibilityAttribute to property</value>
   </data>
-</root>
+</root>

src/System.Windows.Forms/src/Resources/SR.resx

@@ -7015,4 +7015,7 @@ Stack trace where the illegal operation occurred was:
   <data name="FormCaptionTextColorDescr" xml:space="preserve">
     <value>The color of the Form's text caption (title bar text).</value>
   </data>
+  <data name="ControlVisualStylesModeChangedDescr" xml:space="preserve">
+    <value>Event raised whenever the VisualStylesMode property changes.</value>
+  </data>
 </root>

src/System.Windows.Forms/src/System/Windows/Forms/Application.cs

@@ -47,6 +47,7 @@ public sealed partial class Application
 
     private const string DarkModeKeyPath = "HKEY_CURRENT_USER\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Themes\\Personalize";
     private const string DarkModeKey = "AppsUseLightTheme";
+    private const int DarkModeNotAvailable = -1;
 
     /// <summary>
     ///  Events the user can hook into
@@ -247,7 +248,7 @@ internal static bool CustomThreadExceptionHandlerAttached
     ///  Gets the default dark mode for the application. This is the SystemColorMode which either has been set
     ///  by <see cref="SetColorMode(SystemColorMode)"/> or its default value <see cref="SystemColorMode.Classic"/>.
     /// </summary>
-    [Experimental(DiagnosticIDs.ExperimentalDarkMode, UrlFormat = "https://aka.ms/WfoExperimental/{0}")]
+    [Experimental(DiagnosticIDs.ExperimentalDarkMode, UrlFormat = "https://aka.ms/winforms-experimental/{0}")]
     public static SystemColorMode ColorMode =>
         !s_systemColorMode.HasValue
             ? SystemColorMode.Classic
@@ -259,7 +260,7 @@ internal static bool CustomThreadExceptionHandlerAttached
     ///  Sets the default dark mode for the application.
     /// </summary>
     /// <param name="systemColorMode">The default dark mode to set.</param>
-    [Experimental(DiagnosticIDs.ExperimentalDarkMode, UrlFormat = "https://aka.ms/WfoExperimental/{0}")]
+    [Experimental(DiagnosticIDs.ExperimentalDarkMode, UrlFormat = "https://aka.ms/winforms-experimental/{0}")]
     public static void SetColorMode(SystemColorMode systemColorMode)
     {
         try
@@ -305,7 +306,7 @@ public static void SetColorMode(SystemColorMode systemColorMode)
     ///   is essential.
     ///  </para>
     /// </remarks>
-    [Experimental(DiagnosticIDs.ExperimentalVisualStyles, UrlFormat = "https://aka.ms/WfoExperimental/{0}")]
+    [Experimental(DiagnosticIDs.ExperimentalVisualStyles, UrlFormat = "https://aka.ms/winforms-experimental/{0}")]
     public static VisualStylesMode DefaultVisualStylesMode { get; private set; }
 
     /// <summary>
@@ -315,7 +316,7 @@ public static void SetColorMode(SystemColorMode systemColorMode)
     ///  as not setting using <see cref="EnableVisualStyles"/>.
     /// </summary>
     /// <param name="styleSetting">The version of visual styles to set.</param>
-    [Experimental(DiagnosticIDs.ExperimentalVisualStyles, UrlFormat = "https://aka.ms/WfoExperimental/{0}")]
+    [Experimental(DiagnosticIDs.ExperimentalVisualStyles, UrlFormat = "https://aka.ms/winforms-experimental/{0}")]
     public static void SetDefaultVisualStylesMode(VisualStylesMode styleSetting)
     {
         if (styleSetting != DefaultVisualStylesMode)
@@ -360,10 +361,10 @@ private static int GetSystemColorModeInternal()
     {
         if (SystemInformation.HighContrast)
         {
-            return -1;
+            return DarkModeNotAvailable;
         }
 
-        int systemColorMode = -1;
+        int systemColorMode = DarkModeNotAvailable;
 
         // Dark mode is supported when we are >= W11/22000
         // Technically, we could go earlier, but then the APIs we're using weren't officially public.
@@ -374,7 +375,7 @@ private static int GetSystemColorModeInternal()
                 systemColorMode = (Registry.GetValue(
                     keyName: DarkModeKeyPath,
                     valueName: DarkModeKey,
-                    defaultValue: -1) as int?) ?? systemColorMode;
+                    defaultValue: DarkModeNotAvailable) as int?) ?? systemColorMode;
             }
             catch (Exception ex) when (!ex.IsCriticalException())
             {