Address more review feedback.

Author: KlausLoeffelmann

src/System.Windows.Forms/System/Windows/Forms/Control.cs

@@ -7329,18 +7329,6 @@ protected virtual void OnHandleCreated(EventArgs e)
                 SetWindowFont();
             }
 
-#pragma warning disable WFO5001 // Type is for evaluation purposes only and is subject to change or removal in future updates.
-            if (Application.IsDarkModeEnabled && GetStyle(ControlStyles.ApplyThemingImplicitly))
-            {
-                HRESULT result = PInvoke.SetWindowTheme(
-                    hwnd: HWND,
-                    pszSubAppName: $"{DarkModeIdentifier}_{ExplorerThemeIdentifier}",
-                    pszSubIdList: null);
-
-                Debug.Assert(result.Succeeded, "SetWindowTheme failed with HRESULT: " + result);
-            }
-#pragma warning restore WFO5001
-
             HandleHighDpi();
 
             // Restore drag drop status. Ole Initialize happens when the ThreadContext in Application is created.
@@ -9338,26 +9326,11 @@ internal virtual void RecreateHandleCore()
                 }
             }
 
-            // Note, that we need to take DarkMode-theming into account here at a different point in time
-            // compared to when we create the handle for the first time. The reason is that recreating the handle
-            // usually also might recreating the 
-
-#pragma warning disable WFO5001 // Type is for evaluation purposes only and is subject to change or removal in future updates.
-            if (Application.IsDarkModeEnabled
-                && GetStyle(ControlStyles.ApplyThemingImplicitly))
-            {
-                _ = PInvoke.SetWindowTheme(
-                    hwnd: HWND,
-                    pszSubAppName: $"{DarkModeIdentifier}_{ExplorerThemeIdentifier}",
-                    pszSubIdList: null);
-            }
-#pragma warning restore WFO5001
-
             // Note that we need to take DarkMode theming into account at a different point in time
             // than when we create the handle for the first time. The reason is that recreating the handle
             // usually also recreates the handles of any child controls, and we want to
             // ensure that the theming is applied to all child controls as well.
-#pragma warning disable WFO5001 // Type is for evaluation purposes only and is subject to change or removal in future updates.
+#pragma warning disable WFO5001
             if (Application.IsDarkModeEnabled
                 && GetStyle(ControlStyles.ApplyThemingImplicitly))
             {

src/System.Windows.Forms/System/Windows/Forms/Controls/Buttons/Button.cs

@@ -149,27 +149,25 @@ public virtual DialogResult DialogResult
     }
 
 #pragma warning disable WFO5001
-    /// <summary>
-    ///  Defines, whether the control is owner-drawn. Based on this,
-    ///  the UserPaint flags get set, which in turn makes it later
-    ///  a Win32 controls, which we wrap (OwnerDraw == false) or if we
-    ///  draw ourselves. If the user wants to opt out of DarkMode, we cannot
-    ///  force System-Painting for FlatStyle.Standard, so we need to know here
-    ///  and now.
-    /// </summary>
+
+    // Indicates whether this control uses owner drawing, enabling UserPaint and determining
+    // if we wrap the native Win32 control (OwnerDraw == false) or render it ourselves.
+    // Also needed to detect a Dark Mode opt-out for FlatStyle.Standard when system painting
+    // cannot be forced.
     private protected override bool OwnerDraw
     {
         get
         {
             if (Application.IsDarkModeEnabled
-                // The SystemRenderer cannot render images. So, we flip to our
-                // own DarkMode renderer, if we need to render images, except if
+
+                // SystemRenderer cannot draw images, so use our DarkMode renderer when images are needed,
+                // unless implicit theming has been disabled.
                 && GetStyle(ControlStyles.ApplyThemingImplicitly)
-                // the user wants to opt out of implicit DarkMode rendering.
+
+                // Only apply when no image is set to avoid custom rendering without content.
                 && Image is null
-                // And this only counts for FlatStyle.Standard. For the rest,
-                // we're using specific renderers, which check themselves, if
-                // they need to apply Light- or DarkMode.
+
+                // Restrict this logic to FlatStyle.Standard; other styles use their own light/dark checks.
                 && FlatStyle == FlatStyle.Standard)
             {
                 return false;

src/System.Windows.Forms/System/Windows/Forms/Controls/Buttons/ButtonBase.cs

@@ -68,7 +68,6 @@ protected ButtonBase()
                 | ControlStyles.Opaque
                 | ControlStyles.ResizeRedraw
                 | ControlStyles.OptimizedDoubleBuffer
-                // We gain about 2% in painting by avoiding extra GetWindowText calls
                 | ControlStyles.CacheText
                 | ControlStyles.StandardClick,
             true);
@@ -399,6 +398,7 @@ public FlatStyle FlatStyle
             _flatStyle = value;
             LayoutTransaction.DoLayoutIf(AutoSize, ParentInternal, this, PropertyNames.FlatStyle);
             Invalidate();
+
             UpdateOwnerDraw();
         }
     }
@@ -452,13 +452,18 @@ public Image? Image
             StopAnimate();
 
             _image = value;
+
             if (_image is not null)
             {
                 ImageIndex = ImageList.Indexer.DefaultIndex;
                 ImageList = null;
             }
 
+            // If we have an Image, for some flat styles we need to change the rendering approach from
+            // being a wrapper around the Win32 control to being owner-drawn. The Win32 control does not
+            // support images in the same flexible way as we need it.
             UpdateOwnerDraw();
+
             LayoutTransaction.DoLayoutIf(AutoSize, ParentInternal, this, PropertyNames.Image);
             Animate();
             Invalidate();
@@ -1015,7 +1020,6 @@ internal override Size GetPreferredSizeCore(Size proposedConstraints)
         return LayoutUtils.UnionSizes(preferredSize + Padding.Size, MinimumSize);
     }
 
-#pragma warning disable WFO5001
     /// <summary>
     ///  Returns an adapter for Rendering one of the FlatStyles. Note, that we always render
     ///  buttons ourselves, except when the User explicitly requests FlatStyle.System rendering!
@@ -1045,7 +1049,6 @@ internal ButtonBaseAdapter Adapter
 
                 _cachedAdapterType = FlatStyle;
             }
-#pragma warning restore WFO5001
 
             return _adapter;
         }
@@ -1295,6 +1298,10 @@ private void SetFlag(int flag, bool value)
 
     private bool ShouldSerializeImage() => _image is not null;
 
+    // Indicates whether this control uses owner drawing, enabling UserPaint and determining
+    // if we wrap the native Win32 control (OwnerDraw == false) or render it ourselves.
+    // Also needed to detect a Dark Mode opt-out for FlatStyle.Standard when system painting
+    // cannot be forced.
     private protected void UpdateOwnerDraw()
     {
         if (OwnerDraw != GetStyle(ControlStyles.UserPaint))

src/System.Windows.Forms/System/Windows/Forms/Controls/Buttons/CheckBox.cs

@@ -49,7 +49,11 @@ public CheckBox() : base()
         TextAlign = ContentAlignment.MiddleLeft;
     }
 
-    protected override void InitializeControl(int deviceDpi) => ScaleConstants();
+    protected override void InitializeControl(int deviceDpi)
+    {
+        base.InitializeControl(deviceDpi);
+        ScaleConstants();
+    }
 
     private bool AccObjDoDefaultAction { get; set; }
 
@@ -83,9 +87,8 @@ public Appearance Appearance
                 {
                     UpdateStyles();
 
-                    // UpdateStyles should also update the UserDraw flag, but it doesn't.
-                    // Since we hijack FlatStyle.Standard for DarkMode and let that SystemRender,
-                    // the threshold from Normal to Button is important to update the OwnerDraw flag.
+                    // When we change the appearance, we might also either stop or start wrapping the
+                    // win32 control. This is controlled by the OwnerDraw setting.
                     UpdateOwnerDraw();
                 }
 
@@ -95,19 +98,36 @@ public Appearance Appearance
     }
 
 #pragma warning disable WFO5001
+    // Indicates whether this control uses owner drawing, enabling UserPaint and determining
+    // if we wrap the native Win32 control (OwnerDraw == false) or render it ourselves.
+    // Also needed to detect a Dark Mode opt-out for FlatStyle.Standard when system painting
+    // cannot be forced.
+    private protected override bool OwnerDraw
+    {
+        get
+        {
+            if (Application.IsDarkModeEnabled
+
+                // We need wrapping around the Win32 control only for
+                // when we're dealing with a button experience.
+                && Appearance == Appearance.Button
+
+                // SystemRenderer cannot draw images, so use our DarkMode renderer
+                // when images are needed, unless implicit theming has been disabled.
+                && GetStyle(ControlStyles.ApplyThemingImplicitly)
 
-    private protected override bool OwnerDraw =>
-            // We want NO owner draw ONLY when we're
-            // * In Dark Mode
-            // * When _then_ the Appearance is Button
-            // * But then ONLY when we're rendering with FlatStyle.Standard
-            //   (because that would let us usually let us draw with the VisualStyleRenderers,
-            //   which cause HighDPI issues in Dark Mode).
-            (!Application.IsDarkModeEnabled
-                || Appearance != Appearance.Button
-                || FlatStyle != FlatStyle.Standard)
-                && base.OwnerDraw;
+                // Only apply when no image is set to avoid custom rendering without content.
+                && Image is null
 
+                // Restrict this logic to FlatStyle.Standard; other styles use their own light/dark checks.
+                && FlatStyle == FlatStyle.Standard)
+            {
+                return false;
+            }
+
+            return base.OwnerDraw;
+        }
+    }
 #pragma warning restore WFO5001
 
     [SRCategory(nameof(SR.CatPropertyChanged))]
@@ -247,6 +267,7 @@ protected override CreateParams CreateParams
         {
             CreateParams cp = base.CreateParams;
             cp.ClassName = PInvoke.WC_BUTTON;
+
             if (OwnerDraw)
             {
                 cp.Style |= PInvoke.BS_OWNERDRAW;
@@ -261,6 +282,7 @@ protected override CreateParams CreateParams
 
                 // Determine the alignment of the check box
                 ContentAlignment align = RtlTranslateContent(CheckAlign);
+
                 if ((align & AnyRight) != 0)
                 {
                     cp.Style |= PInvoke.BS_RIGHTBUTTON;

src/System.Windows.Forms/System/Windows/Forms/Controls/Buttons/RadioButton.cs

@@ -50,6 +50,12 @@ public RadioButton() : base()
         SetAutoSizeMode(AutoSizeMode.GrowAndShrink);
     }
 
+    protected override void InitializeControl(int deviceDpi)
+    {
+        base.InitializeControl(deviceDpi);
+        ScaleConstants();
+    }
+
     /// <summary>
     ///  Gets or sets a value indicating whether the <see cref="Checked"/> value and the appearance of
     ///  the control automatically change when the control is clicked.
@@ -97,7 +103,8 @@ public Appearance Appearance
                     {
                         UpdateStyles();
 
-                        // UpdateStyles should also update the UserDraw flag, but it doesn't.
+                        // When we change the appearance, we might also either stop or start wrapping the
+                        // win32 control. This is controlled by the OwnerDraw setting.
                         UpdateOwnerDraw();
                     }
 
@@ -172,18 +179,36 @@ public bool Checked
     }
 
 #pragma warning disable WFO5001
-    private protected override bool OwnerDraw =>
-        // Order is key here - do NOT change!
-        // We want NO owner draw ONLY when we're
-        // * in Dark Mode
-        // * when _then_ the Appearance is Button
-        // * but then ONLY when we're rendering with FlatStyle.Standard
-        //   (because that would let us usually let us draw with the VisualStyleRenderers,
-        //   which cause HighDPI issues in Dark Mode).
-        (!Application.IsDarkModeEnabled
-            || Appearance != Appearance.Button
-            || FlatStyle != FlatStyle.Standard)
-            && base.OwnerDraw;
+    // Indicates whether this control uses owner drawing, enabling UserPaint and determining
+    // if we wrap the native Win32 control (OwnerDraw == false) or render it ourselves.
+    // Also needed to detect a Dark Mode opt-out for FlatStyle.Standard when system painting
+    // cannot be forced.
+    private protected override bool OwnerDraw
+    {
+        get
+        {
+            if (Application.IsDarkModeEnabled
+
+                // We need wrapping around the Win32 control only for
+                // when we're dealing with a button experience.
+                && Appearance == Appearance.Button
+
+                // SystemRenderer cannot draw images, so use our DarkMode renderer
+                // when images are needed, unless implicit theming has been disabled.
+                && GetStyle(ControlStyles.ApplyThemingImplicitly)
+
+                // Only apply when no image is set to avoid custom rendering without content.
+                && Image is null
+
+                // Restrict this logic to FlatStyle.Standard; other styles use their own light/dark checks.
+                && FlatStyle == FlatStyle.Standard)
+            {
+                return false;
+            }
+
+            return base.OwnerDraw;
+        }
+    }
 #pragma warning restore WFO5001
 
     /// <hideinheritance/>
@@ -210,6 +235,7 @@ protected override CreateParams CreateParams
         {
             CreateParams cp = base.CreateParams;
             cp.ClassName = PInvoke.WC_BUTTON;
+
             if (OwnerDraw)
             {
                 cp.Style |= PInvoke.BS_OWNERDRAW;
@@ -259,8 +285,6 @@ private void ScaleConstants()
         _flatSystemStyleMinimumHeight = LogicalToDeviceUnits(LogicalFlatSystemStyleMinimumHeight);
     }
 
-    protected override void InitializeControl(int deviceDpi) => ScaleConstants();
-
     internal override Size GetPreferredSizeCore(Size proposedConstraints)
     {
         if (FlatStyle != FlatStyle.System)

src/System.Windows.Forms/System/Windows/Forms/Controls/TabControl/TabControl.cs

@@ -2022,7 +2022,6 @@ private unsafe void WmTabBaseReLayout()
 
         // Remove other TabBaseReLayout messages from the message queue
         MSG msg = default;
-
         while (PInvokeCore.PeekMessage(
             &msg,
             this,

src/System.Windows.Forms/System/Windows/Forms/Controls/ToolStrips/ToolStripRenderer.cs

@@ -666,26 +666,26 @@ private protected Point[] RenderArrowCore(
             ArrowDirection.Up =>
             [
                 new(middle.X - Offset2X, middle.Y + 1),
-            new(middle.X + Offset2X + 1, middle.Y + 1),
-            new(middle.X, middle.Y - Offset2Y)
+                new(middle.X + Offset2X + 1, middle.Y + 1),
+                new(middle.X, middle.Y - Offset2Y)
             ],
             ArrowDirection.Left =>
             [
                 new(middle.X + Offset2X, middle.Y - s_offset4Y),
-            new(middle.X + Offset2X, middle.Y + s_offset4Y),
-            new(middle.X - horizontalOffset, middle.Y)
+                new(middle.X + Offset2X, middle.Y + s_offset4Y),
+                new(middle.X - horizontalOffset, middle.Y)
             ],
             ArrowDirection.Right =>
             [
                 new(middle.X - Offset2X, middle.Y - s_offset4Y),
-            new(middle.X - Offset2X, middle.Y + s_offset4Y),
-            new(middle.X + horizontalOffset, middle.Y)
+                new(middle.X - Offset2X, middle.Y + s_offset4Y),
+                new(middle.X + horizontalOffset, middle.Y)
             ],
             _ =>
             [
                 new(middle.X - Offset2X, middle.Y - 1),
-            new(middle.X + Offset2X + 1, middle.Y - 1),
-            new(middle.X, middle.Y + Offset2Y)
+                new(middle.X + Offset2X + 1, middle.Y - 1),
+                new(middle.X, middle.Y + Offset2Y)
             ],
         };
 
@@ -1121,18 +1121,18 @@ private protected static void OnRenderStatusStripSizingGrip(
             // Default values
             (int offset, Rectangle rect) cornerDef = (2, new(1, 1, 2, 2));
 
+#pragma warning disable WFO5001 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
             if (Environment.OSVersion.Version >= new Version(10, 0, 22000)
                 && statusStrip.FindForm() is Form f)
             {
-#pragma warning disable WFO5001 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
                 cornerDef = f.FormCornerPreference switch
                 {
                     FormCornerPreference.Round => (4, new(1, 1, 2, 2)),
                     FormCornerPreference.RoundSmall => (3, new(1, 1, 2, 2)),
                     _ => (2, new(0, 0, 2, 2))
                 };
-#pragma warning restore WFO5001 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
             }
+#pragma warning restore WFO5001 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
 
             return cornerDef;
         }