Dark mode - amended concept for SystemColors issue.

.editorconfig

@@ -70,13 +70,13 @@ dotnet_naming_style.camel_case_underscore_style.capitalization = camel_case
 dotnet_sort_system_directives_first = true
 
 # Expression-level preferences
-dotnet_style_object_initializer = true:warning
+dotnet_style_object_initializer = true:suggestion
 dotnet_style_collection_initializer = true:suggestion
 dotnet_style_explicit_tuple_names = true:suggestion
-dotnet_style_null_propagation = true:warning
-dotnet_style_prefer_is_null_check_over_reference_equality_method = true:error
+dotnet_style_null_propagation = true:suggestion
+dotnet_style_prefer_is_null_check_over_reference_equality_method = true:suggestion
 dotnet_style_prefer_auto_properties = true:silent
-dotnet_style_prefer_simplified_boolean_expressions = true:warning
+dotnet_style_prefer_simplified_boolean_expressions = true:suggestion
 dotnet_style_prefer_inferred_tuple_names = true:suggestion
 dotnet_style_prefer_inferred_anonymous_type_member_names = true:suggestion
 dotnet_style_prefer_compound_assignment = true:suggestion
@@ -319,6 +319,9 @@ dotnet_diagnostic.CA5397.severity = warning
 
 # RS0041: Public members should not use oblivious types
 dotnet_diagnostic.RS0041.severity = warning
+dotnet_style_coalesce_expression = true:suggestion
+dotnet_style_prefer_conditional_expression_over_assignment = true:silent
+dotnet_style_prefer_conditional_expression_over_return = true:silent
 
 # C# files
 
@@ -497,6 +500,12 @@ dotnet_diagnostic.CA2016.severity = warning
 # CA2020: Prevent behavioral change caused by built-in operators of IntPtr/UIntPtr 
 dotnet_diagnostic.CA2020.severity = warning
 
+# WFO9000:
+dotnet_diagnostic.WFO9000.severity = silent
+
+# WFO9001:
+dotnet_diagnostic.WFO9001.severity = silent
+
 # .NET diagnostic
 dotnet_diagnostic.RS0041.severity = none
 dotnet_diagnostic.IDE0005.severity = error
@@ -532,9 +541,9 @@ csharp_preserve_single_line_blocks = true
 csharp_preserve_single_line_statements = false
 
 # Expression-bodied members
-csharp_style_expression_bodied_methods = true:silent
-csharp_style_expression_bodied_constructors = true:silent
-csharp_style_expression_bodied_operators = true:silent
+csharp_style_expression_bodied_methods = false:silent
+csharp_style_expression_bodied_constructors = false:silent
+csharp_style_expression_bodied_operators = false:silent
 csharp_style_expression_bodied_properties = true:silent
 csharp_style_expression_bodied_indexers = true:silent
 csharp_style_expression_bodied_accessors = true:silent
@@ -572,12 +581,12 @@ csharp_space_between_method_declaration_parameter_list_parentheses = false
 csharp_space_between_parentheses = false
 csharp_space_between_square_brackets = false
 csharp_using_directive_placement = outside_namespace:silent
-csharp_prefer_simple_using_statement = true:warning
+csharp_prefer_simple_using_statement = true:suggestion
 csharp_prefer_braces = true:silent
-csharp_style_namespace_declarations = file_scoped:silent
+csharp_style_namespace_declarations = block_scoped:silent
 csharp_style_prefer_method_group_conversion = true:silent
 csharp_style_prefer_top_level_statements = true:silent
-csharp_style_prefer_primary_constructors = true:silent
+csharp_style_prefer_primary_constructors = true:suggestion
 csharp_style_expression_bodied_lambdas = true:silent
 csharp_style_expression_bodied_local_functions = false:silent
 csharp_style_allow_embedded_statements_on_same_line_experimental = true:silent
@@ -586,6 +595,7 @@ csharp_style_allow_blank_line_after_colon_in_constructor_initializer_experimenta
 csharp_style_allow_blank_line_after_token_in_conditional_expression_experimental = true:silent
 csharp_style_allow_blank_line_after_token_in_arrow_expression_clause_experimental = true:silent
 csharp_style_deconstructed_variable_declaration = true:suggestion
+csharp_prefer_system_threading_lock = true:suggestion
 
 # Visual Basic files
 

src/Microsoft.VisualBasic.Forms/src/Microsoft.VisualBasic.Forms.vbproj

@@ -9,7 +9,7 @@
     <AssemblyName>Microsoft.VisualBasic.Forms</AssemblyName>
     <Deterministic>true</Deterministic>
     <RootNamespace></RootNamespace>
-    <LangVersion>15.0</LangVersion>
+    <LangVersion>15.5</LangVersion>
     <VBRuntime>None</VBRuntime>
     <ProduceReferenceAssembly>true</ProduceReferenceAssembly>
     <UsePublicApiAnalyzers>true</UsePublicApiAnalyzers>

src/System.Private.Windows.Core/src/NativeMethods.txt

@@ -13,6 +13,7 @@ CreateDIBSection
 CreateFontIndirect
 CreateICW
 CreateRectRgn
+CreateRoundRectRgn
 DeleteDC
 DeleteObject
 DestroyIcon
@@ -57,6 +58,7 @@ E_OUTOFMEMORY
 E_POINTER
 E_UNEXPECTED
 EncoderParameters
+ExtSelectClipRgn
 fdex*
 FDEX_PROP_FLAGS
 FILETIME
@@ -94,6 +96,7 @@ GetSystemMetrics
 GetThreadLocale
 GetViewportExtEx
 GetViewportOrgEx
+GetWindowDC
 GlobalAlloc
 GlobalFree
 GlobalLock
@@ -142,7 +145,9 @@ MonitorFromWindow
 MONITORINFOEXW
 MONITORINFOF_*
 NONCLIENTMETRICSW
+NCCALCSIZE_PARAMS
 OBJ_TYPE
+OffsetClipRgn
 OffsetViewportOrgEx
 OLE_E_ADVISENOTSUPPORTED
 OLE_E_INVALIDRECT

src/System.Windows.Forms.Design/src/System/ComponentModel/Design/DesignerActionPanel.EditorPropertyLine.cs

@@ -108,7 +108,7 @@ private unsafe void ActivateDropDown()
 
                 try
                 {
-                    ShowDropDown(listBox, SystemColors.ControlDark);
+                    ShowDropDown(listBox, Drawing.SystemColors.ControlDark);
                 }
                 finally
                 {

src/System.Windows.Forms.Design/src/System/ComponentModel/Design/DesignerActionPanel.TextBoxPropertyLine.cs

@@ -32,7 +32,7 @@ protected TextBoxPropertyLine(IServiceProvider serviceProvider, DesignerActionPa
             _readOnlyTextBoxLabel = new EditorLabel
             {
                 BackColor = Color.Transparent,
-                ForeColor = SystemColors.WindowText,
+                ForeColor = Drawing.SystemColors.WindowText,
                 TabStop = true,
                 TextAlign = ContentAlignment.TopLeft,
                 UseMnemonic = false,
@@ -159,14 +159,14 @@ protected virtual void OnReadOnlyTextBoxLabelClick(object? sender, MouseEventArg
 
         private void OnReadOnlyTextBoxLabelEnter(object? sender, EventArgs e)
         {
-            _readOnlyTextBoxLabel.ForeColor = SystemColors.HighlightText;
-            _readOnlyTextBoxLabel.BackColor = SystemColors.Highlight;
+            _readOnlyTextBoxLabel.ForeColor = Drawing.SystemColors.HighlightText;
+            _readOnlyTextBoxLabel.BackColor = Drawing.SystemColors.Highlight;
         }
 
         private void OnReadOnlyTextBoxLabelLeave(object? sender, EventArgs e)
         {
-            _readOnlyTextBoxLabel.ForeColor = SystemColors.WindowText;
-            _readOnlyTextBoxLabel.BackColor = SystemColors.Window;
+            _readOnlyTextBoxLabel.ForeColor = Drawing.SystemColors.WindowText;
+            _readOnlyTextBoxLabel.BackColor = Drawing.SystemColors.Window;
         }
 
         protected TypeConverter.StandardValuesCollection? GetStandardValues()

src/System.Windows.Forms.Design/src/System/ComponentModel/Design/DesignerActionPanel.cs

@@ -117,9 +117,9 @@ public DesignerActionPanel(IServiceProvider serviceProvider)
         MinimumSize = new Size(150, 0);
     }
 
-    public Color ActiveLinkColor { get; } = SystemColors.HotTrack;
+    public Color ActiveLinkColor { get; } = Drawing.SystemColors.HotTrack;
 
-    public Color BorderColor { get; } = SystemColors.ActiveBorder;
+    public Color BorderColor { get; } = Drawing.SystemColors.ActiveBorder;
 
     /// <summary>
     ///  Returns the list of commands that should be filtered by the form that hosts this panel. This is done so that these specific commands will not get passed on to VS, and can instead be handled by the panel itself.
@@ -167,23 +167,23 @@ public DesignerActionPanel(IServiceProvider serviceProvider)
     /// </summary>
     private Line? FocusedLine => ActiveControl?.Tag as Line;
 
-    public Color GradientDarkColor { get; } = SystemColors.Control;
+    public Color GradientDarkColor { get; } = Drawing.SystemColors.Control;
 
-    public Color GradientLightColor { get; } = SystemColors.Control;
+    public Color GradientLightColor { get; } = Drawing.SystemColors.Control;
 
     public bool InMethodInvoke { get; internal set; }
 
-    public Color LinkColor { get; } = SystemColors.HotTrack;
+    public Color LinkColor { get; } = Drawing.SystemColors.HotTrack;
 
-    public Color SeparatorColor { get; } = SystemColors.ControlDark;
+    public Color SeparatorColor { get; } = Drawing.SystemColors.ControlDark;
 
-    public Color TitleBarColor { get; } = SystemColors.ActiveCaption;
+    public Color TitleBarColor { get; } = Drawing.SystemColors.ActiveCaption;
 
-    public Color TitleBarTextColor { get; } = SystemColors.ActiveCaptionText;
+    public Color TitleBarTextColor { get; } = Drawing.SystemColors.ActiveCaptionText;
 
-    public Color TitleBarUnselectedColor { get; } = SystemColors.InactiveCaption;
+    public Color TitleBarUnselectedColor { get; } = Drawing.SystemColors.InactiveCaption;
 
-    public Color LabelForeColor { get; } = SystemColors.ControlText;
+    public Color LabelForeColor { get; } = Drawing.SystemColors.ControlText;
 
     /// <summary>
     ///  Helper event so that Lines can be notified of this event.

src/System.Windows.Forms.Design/src/System/Drawing/Design/ColorEditor.ColorUI.cs

@@ -70,7 +70,7 @@ private Color[] CustomColors
         /// <summary>
         ///  Array of system colors.
         /// </summary>
-        private Color[] SystemColorValues => _systemColorConstants ??= GetConstants(typeof(SystemColors));
+        private Color[] SystemColorValues => _systemColorConstants ??= GetConstants(typeof(ControlSystemColors));
 
         public object? Value => _value;
 

src/System.Windows.Forms.Design/src/System/Windows/Forms/Design/SelectionUIService.SelectionUIItem.cs

@@ -135,7 +135,7 @@ public virtual void DoPaint(Graphics graphics)
             Rectangle inner = _innerRect;
             Rectangle outer = _outerRect;
             Region oldClip = graphics.Clip;
-            Color borderColor = SystemColors.Control;
+            Color borderColor = Drawing.SystemColors.Control;
             if (_control is not null && _control.Parent is not null)
             {
                 Control parent = _control.Parent;

src/System.Windows.Forms.Primitives/src/NativeMethods.txt

@@ -108,6 +108,8 @@ DSH_FLAGS
 DTM_*
 DTN_*
 DTS_*
+DwmSetWindowAttribute
+DWM_WINDOW_CORNER_PREFERENCE
 DuplicateHandle
 EC_*
 ECO_*
@@ -135,6 +137,7 @@ EXTLOGFONTW
 ExtTextOut
 FDAP
 FillRect
+FillRgn
 FindExecutable
 FINDREPLACE_FLAGS
 FindWindow
@@ -164,6 +167,7 @@ GetClipboardFormatName
 GetClipBox
 GetClipCursor
 GetClipRgn
+GetComboBoxInfo
 GetCurrentActCtx
 GetCurrentObject
 GetCurrentProcess
@@ -600,6 +604,7 @@ SetActiveWindow
 SetBkColor
 SetBkMode
 SetCapture
+SetCaretPos
 SetCursor
 SetCursorPos
 SetFocus

src/System.Windows.Forms.Primitives/src/Windows/Win32/PInvoke.FillRgn.cs

@@ -0,0 +1,17 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace Windows.Win32;
+
+internal static partial class PInvoke
+{
+    /// <inheritdoc cref="FillRgn(HDC, HRGN, HBRUSH)"/>
+    public static int FillRgn<T>(T hDC, ref HRGN hRgn, HBRUSH hbr)
+        where T : IHandle<HDC>
+    {
+        int result = FillRgn(hDC.Handle, hRgn, hbr);
+        GC.KeepAlive(hDC.Wrapper);
+
+        return result;
+    }
+}

src/System.Windows.Forms/src/PublicAPI.Shipped.txt

@@ -9983,8 +9983,6 @@ System.Windows.Forms.TextBoxBase.Modified.set -> void
 System.Windows.Forms.TextBoxBase.ModifiedChanged -> System.EventHandler?
 System.Windows.Forms.TextBoxBase.MouseClick -> System.Windows.Forms.MouseEventHandler?
 System.Windows.Forms.TextBoxBase.MultilineChanged -> System.EventHandler?
-System.Windows.Forms.TextBoxBase.Padding.get -> System.Windows.Forms.Padding
-System.Windows.Forms.TextBoxBase.Padding.set -> void
 System.Windows.Forms.TextBoxBase.PaddingChanged -> System.EventHandler?
 System.Windows.Forms.TextBoxBase.Paint -> System.Windows.Forms.PaintEventHandler?
 System.Windows.Forms.TextBoxBase.Paste() -> void