Skip to content

Fix issue 14859: CheckBox and RadioButton ignore explicit BackColor values in VisualStylesMode.Net11 #14865

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
SimonZhao888 wants to merge 3 commits into
base: main
Choose a base branch
from
Open

Fix issue 14859: CheckBox and RadioButton ignore explicit BackColor values in VisualStylesMode.Net11 #14865

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
9fd5f98
Fix issue 14859: CheckBox and RadioButton ignore explicit BackColor v…
Aug 7, 2026
a7e2280
Merge branch 'main' into Fix_Issue_14859
Aug 10, 2026
d95d37f
Sync the latest code and apply relevant fixes.
Aug 10, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
37 changes: 24 additions & 13 deletions ...ndows.Forms/System/Windows/Forms/Controls/Buttons/ButtonInternal/CheckBoxModernAdapter.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
// Licensed to the .NET Foundation under one or more agreements.
// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System.Drawing;
Expand Down Expand Up @@ -80,21 +80,27 @@ internal override LayoutOptions CommonLayout()
private void PaintCore(PaintEventArgs e)
{
Graphics graphics = e.GraphicsInternal;
ParentBackgroundRenderer.Paint(
Control,
graphics,
Control.ClientRectangle,
Control.BackColor);
bool useControlBackColor = !Control.BackColor.HasTransparency()
&& (Control.ShouldSerializeBackColor() || !Control.UseVisualStyleBackColor);

@LeafShi1 LeafShi1 Aug 11, 2026

Copy link
Copy Markdown
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Explicit translucent BackColor values are still ignored here. ButtonBase supports transparent back colors, but when HasTransparency() is true this falls through to ParentBackgroundRenderer.Paint. With a parent, that helper paints only the parent background; Control.BackColor is merely a no-parent fallback and is never composited over it. For example, a 50%-alpha Aqua BackColor on a white parent still renders white. Please paint the parent first and then overlay the translucent control color. The same issue exists in RadioButtonModernAdapter.


if (useControlBackColor)
{
using var backBrush = Control.BackColor.GetCachedSolidBrushScope();
graphics.FillRectangle(backBrush, Control.ClientRectangle);
}
else
{
ParentBackgroundRenderer.Paint(
Control,
graphics,
Control.ClientRectangle,
Control.BackColor);
}

LayoutData layout = Layout(e).Layout();
AdjustFocusRectangle(layout);
PaintBackgroundImage(e);

Color? customOnColor = Control.ShouldSerializeBackColor()
&& Control.BackColor.A == byte.MaxValue
? Control.BackColor
: null;

Color? customBorderColor = Control.FlatAppearance.BorderColor.IsEmpty
? null
: Control.FlatAppearance.BorderColor;
Expand All @@ -107,7 +113,7 @@ private void PaintCore(PaintEventArgs e)
Control.Enabled,
Control.MouseIsOver,
Control.Focused && Control.ShowFocusCues,
customOnColor,
customOnColor: null,
customBorderColor);

PaintImage(e, layout);
Expand All @@ -117,11 +123,16 @@ private void PaintCore(PaintEventArgs e)
: Application.IsDarkModeEnabled
? Color.FromArgb(0xF0, 0xF0, 0xF0)
: SystemColors.WindowText;
Color disabledTextBackColor = Control.ShouldSerializeBackColor()
&& Control.BackColor.A == byte.MaxValue
? Control.BackColor
: Control.Parent?.BackColor ?? Control.BackColor;

Color textColor = Control.Enabled
? preferredTextColor
: ModernControlColorMath.GetDisabledTextColor(
preferredTextColor,
Control.Parent?.BackColor ?? Control.BackColor);
disabledTextBackColor);

PaintField(e, layout, PaintRender(e).Calculate(), textColor, drawFocus: true);
}
Expand Down
37 changes: 24 additions & 13 deletions ...ws.Forms/System/Windows/Forms/Controls/Buttons/ButtonInternal/RadioButtonModernAdapter.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
// Licensed to the .NET Foundation under one or more agreements.
// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System.Drawing;
Expand Down Expand Up @@ -79,21 +79,27 @@ internal override LayoutOptions CommonLayout()
private void PaintCore(PaintEventArgs e)
{
Graphics graphics = e.GraphicsInternal;
ParentBackgroundRenderer.Paint(
Control,
graphics,
Control.ClientRectangle,
Control.BackColor);
bool useControlBackColor = !Control.BackColor.HasTransparency()
&& (Control.ShouldSerializeBackColor() || !Control.UseVisualStyleBackColor);

if (useControlBackColor)
{
using var backBrush = Control.BackColor.GetCachedSolidBrushScope();
graphics.FillRectangle(backBrush, Control.ClientRectangle);
}
else
{
ParentBackgroundRenderer.Paint(
Control,
graphics,
Control.ClientRectangle,
Control.BackColor);
}

LayoutData layout = Layout(e).Layout();
AdjustFocusRectangle(layout);
PaintBackgroundImage(e);

Color? customOnColor = Control.ShouldSerializeBackColor()
&& Control.BackColor.A == byte.MaxValue
? Control.BackColor
: null;

Color? customBorderColor = Control.FlatAppearance.BorderColor.IsEmpty
? null
: Control.FlatAppearance.BorderColor;
Expand All @@ -106,7 +112,7 @@ private void PaintCore(PaintEventArgs e)
Control.Enabled,
Control.MouseIsOver,
Control.Focused && Control.ShowFocusCues,
customOnColor,
customOnColor: null,
customBorderColor);

PaintImage(e, layout);
Expand All @@ -116,11 +122,16 @@ private void PaintCore(PaintEventArgs e)
: Application.IsDarkModeEnabled
? Color.FromArgb(0xF0, 0xF0, 0xF0)
: SystemColors.WindowText;
Color disabledTextBackColor = Control.ShouldSerializeBackColor()
&& Control.BackColor.A == byte.MaxValue
? Control.BackColor
: Control.Parent?.BackColor ?? Control.BackColor;

Color textColor = Control.Enabled
? preferredTextColor
: ModernControlColorMath.GetDisabledTextColor(
preferredTextColor,
Control.Parent?.BackColor ?? Control.BackColor);
disabledTextBackColor);

PaintField(e, layout, PaintRender(e).Calculate(), textColor, drawFocus: true);
}
Expand Down
34 changes: 32 additions & 2 deletions src/test/unit/System.Windows.Forms/System/Windows/Forms/CheckBoxTests.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -571,7 +571,7 @@ public void CheckBox_AppearanceChanged_RecreatesModernAdapter()
[InlineData(CheckState.Unchecked, false)]
[InlineData(CheckState.Checked, true)]
[InlineData(CheckState.Indeterminate, true)]
public void CheckBox_ModernGlyph_RendersAccentForCheckedStates(CheckState checkState, bool expectedAccent)
public void CheckBox_ModernGlyph_UsesExplicitBackColorWithoutTintingCheckedGlyph(CheckState checkState, bool expectedAccent)
{
if (SystemInformation.HighContrast)
{
Expand All @@ -582,6 +582,7 @@ public void CheckBox_ModernGlyph_RendersAccentForCheckedStates(CheckState checkS
using CheckBox box = new()
{
BackColor = Color.Red,
UseVisualStyleBackColor = true,
CheckState = checkState,
Size = new Size(40, 24),
VisualStylesMode = VisualStylesMode.Net11
Expand All @@ -594,7 +595,36 @@ public void CheckBox_ModernGlyph_RendersAccentForCheckedStates(CheckState checkS

box.CreateStandardAdapter().PaintUp(e, checkState);

Assert.Equal(expectedAccent, CountPixels(bitmap, Color.Red) > 0);
Color backgroundPixel = bitmap.GetPixel(box.Width - 2, box.Height / 2);
Assert.Equal(Color.Red.ToArgb(), backgroundPixel.ToArgb());
Assert.Equal(
expectedAccent,

@LeafShi1 LeafShi1 Aug 11, 2026

Copy link
Copy Markdown
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This assertion is environment-dependent because the entire control background is Color.Red. If the Windows Accent color is red, the unchecked case finds the background pixels and reports an accent glyph that was never drawn. Please choose a background color guaranteed to differ from Application.SystemVisualSettings.AccentColor (and make the equivalent change in RadioButtonTests).

CountPixels(bitmap, Application.SystemVisualSettings.AccentColor) > 0);
}

[WinFormsFact]
public void CheckBox_ModernGlyph_UsesExplicitBackColorWhenVisualStyleBackgroundDisabled()
{
using Panel parent = new() { BackColor = Color.White };
using CheckBox box = new()
{
BackColor = Color.Aqua,
CheckState = CheckState.Unchecked,
Text = string.Empty,
Size = new Size(40, 24),
VisualStylesMode = VisualStylesMode.Net11
};

parent.Controls.Add(box);

using Bitmap bitmap = new(box.Width, box.Height);
using Graphics graphics = Graphics.FromImage(bitmap);
PaintEventArgs e = new(graphics, box.ClientRectangle);

box.CreateStandardAdapter().PaintUp(e, box.CheckState);

Color backgroundPixel = bitmap.GetPixel(box.Width - 2, box.Height / 2);
Assert.Equal(Color.Aqua.ToArgb(), backgroundPixel.ToArgb());
}

[WinFormsFact]
Expand Down
34 changes: 32 additions & 2 deletions src/test/unit/System.Windows.Forms/System/Windows/Forms/RadioButtonTests.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -209,7 +209,7 @@ public void RadioButton_AppearanceChanged_RecreatesModernAdapter()
[WinFormsTheory]
[InlineData(false, false)]
[InlineData(true, true)]
public void RadioButton_ModernGlyph_RendersAccentWhenChecked(bool isChecked, bool expectedAccent)
public void RadioButton_ModernGlyph_UsesExplicitBackColorWithoutTintingCheckedGlyph(bool isChecked, bool expectedAccent)
{
if (SystemInformation.HighContrast)
{
Expand All @@ -220,6 +220,7 @@ public void RadioButton_ModernGlyph_RendersAccentWhenChecked(bool isChecked, boo
using RadioButton control = new()
{
BackColor = Color.Red,
UseVisualStyleBackColor = true,
Checked = isChecked,
Size = new Size(40, 24),
VisualStylesMode = VisualStylesMode.Net11
Expand All @@ -234,7 +235,36 @@ public void RadioButton_ModernGlyph_RendersAccentWhenChecked(bool isChecked, boo
e,
isChecked ? CheckState.Checked : CheckState.Unchecked);

Assert.Equal(expectedAccent, CountPixels(bitmap, Color.Red) > 0);
Color backgroundPixel = bitmap.GetPixel(control.Width - 2, control.Height / 2);
Assert.Equal(Color.Red.ToArgb(), backgroundPixel.ToArgb());
Assert.Equal(
expectedAccent,
CountPixels(bitmap, Application.SystemVisualSettings.AccentColor, channelTolerance: 24) > 0);
}

[WinFormsFact]
public void RadioButton_ModernGlyph_UsesExplicitBackColorWhenVisualStyleBackgroundDisabled()
{
using Panel parent = new() { BackColor = Color.White };
using RadioButton control = new()
{
BackColor = Color.Aqua,
Checked = false,
Text = string.Empty,
Size = new Size(40, 24),
VisualStylesMode = VisualStylesMode.Net11
};

parent.Controls.Add(control);

using Bitmap bitmap = new(control.Width, control.Height);
using Graphics graphics = Graphics.FromImage(bitmap);
PaintEventArgs e = new(graphics, control.ClientRectangle);

control.CreateStandardAdapter().PaintUp(e, CheckState.Unchecked);

Color backgroundPixel = bitmap.GetPixel(control.Width - 2, control.Height / 2);
Assert.Equal(Color.Aqua.ToArgb(), backgroundPixel.ToArgb());
}

[WinFormsFact]
Expand Down