CheckBox and RadioButton ignore BackColor and ForeColor when Appearance=Button in Dark Mode

[Amy-Li03]

.NET version

.NET 11.0.100-rc.1.26404.113

Did it work in .NET Framework?

Not tested/verified

Did it work in any of the earlier releases of .NET Core or .NET 5+?

No, this issue also repro on .NET10

Issue description

When CheckBox.Appearance or RadioButton.Appearance is set to Appearance.Button,
custom BackColor and ForeColor values are ignored in Dark Mode.
The controls are rendered using the system button theme colors instead of the user-specified colors.

Regular Button controls honor the same color settings correctly.

Steps to reproduce

1. Create a WinForms .NET application with RadioButton/CheckBox control
2. Set RadioButton/CheckBox's Appearanceis Button
3. Custom RadioButton/CheckBox's BackColor and ForeColor
4. Enable DarkMode by Application.SetColorMode(SystemColorMode.Dark) in Program.cs file
5. Run the application to observe

[SimonZhao888]

Hi @KlausLoeffelmann,

Could you please take a look at this issue? From the code below, it looks like the current behavior may be intentional rather than a regression.

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

Lines 98 to 113 in 1156c7f

	private protected override bool OwnerDraw =>
	// Appearance.ToggleSwitch intentionally wins over FlatStyle.System: a toggle has no
	// native BS_GROUPBOX rendering and must remain owner-drawn so the requested appearance
	// is never ignored and mouse-state geometry is always available.
	IsToggleSwitchAppearance
	||
	// 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);

With the new .NET 11 visual styles, do you think CheckBox and RadioButton should continue to honor this behavior?