dotnet/winforms

[Dark Mode] The Form title bar is white color when the MDIParent1 MainMenuStrip property is set to none

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#12,991 建立於 2025年2月20日

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 (2 留言) (1 反應) (1 負責人)C# (4,100 star) (922 fork)batch import
area-DarkModehelp wanted

描述

.NET version

.NET 10.0.100-preview.2.25118.3

Did it work in .NET Framework?

No

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

No, also repro in .NET 9.0 which it started to be supported.

Issue description

The Form title bar is white color when the MDIParent1 MainMenuStrip property is set to none.

Image

https://github.com/user-attachments/assets/f0a3ce9b-9f6f-45a0-a14f-52be1c43d662

Steps to reproduce

  1. Create a winforms .NET Core project.
  2. Enable DarkMode by Application.SetColorMode(SystemColorMode.Dark) in Program.cs file.
  3. Ctrl+Shift+A to add a MDI Parent Form.
  4. Set MDIParent1 MainMenuStrip property to none.
  5. Build and run MDIParent1.
  6. Click File -> New, select Window0's Maximize button.

More Info:

  1. This issue also repro when click MDI Parent button in WinformsControlTest app.

Image

貢獻者指南

技術棧
csharp
領域
desktop
議題類型
bug
難度面向新貢獻者的預計實作難度，1 表示很小改動，5 表示專家級工作。
3
預計時間有經驗貢獻者完成調查、實作、測試並準備 pull request 的粗略時間範圍。
half day
活動狀態議題目前的可參與程度：新鮮、活躍、陳舊、阻塞或等待維護者輸入。
blocked
清晰度議題是否清楚說明預期改動、驗收標準和下一步。
clear
前置要求
C#Windows FormsDark mode themingMDI
新手友善度1-100 的估計分數，表示該議題對首次貢獻者的友善程度。
40
研究方向
This issue relates to the dark mode title bar color when MainMenuStrip is null. Investigate the rendering logic in the Form's title bar and MDI client area, possibly in files such as 'Form.cs' or 'MdiClient.cs' within the System.Windows.Forms source. Review the existing dark mode implementation and check how the title bar color is determined when MainMenuStrip is not set. Look at recent changes related to dark mode in the repository to identify the root cause.