The FormCaptionTextColorChanged event property of the Form does not work

[Nora-Zhou01]

.NET version

.NET SDK 9.0.100-rc.1.24415.1 + build private dll form winforms repo release/9.0 branch

Did it work in .NET Framework?

No

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

No, this is a new feature Dark Mode: #11857

Issue description

Form's FormCaptionTextColorChanged event property doesn't work, can't display text color correctly.
Actual result:

Expected result:
The FormCaptionTextColorChanged event of the Form should display the text color correctly.

Steps to reproduce

1. Launch theFormCaptionTextColorChanged-TestApp.zip project in VS and run it.
2. Observe the value in textbox control.

[Zheng-Li01]

Verified the issue with .NET SDK 9.0.100-rc.2.24420.21 + private dlls built from winforms repo main branch , the issue has been fixed that the FormCaptionTextColorChanged event property of the Form work working well as below screenshot.

[Nora-Zhou01]

Verified this issue in the latest .NET 9 RC1 build: 9.0.100-rc.1.24421.9 from https://aka.ms/dotnet/9.0.1xx-rc1/daily/dotnet-sdk-win-x64.exe, it was fixed:

[Zheng-Li01]

Verified the issue with .NET 9.0.100-rc.1.24422.10 test pass build, the issue has been fixed that have the same results as above.

[John-Qiao]

Verified this issue in the latest .NET9.0 SDK build: 9.0.100-rc.2.24428.6, it was fixed. Same test result as above.

[Zheng-Li01]

Verified the issue with .NET 9.0.100-rc.1.24452.12 test pass build that the issue has been fixed that have the same results as above.

[Nora-Zhou01]

Verified the issue with .NET 9.0.100-rc.2.24474.11 test pass build that the issue has been fixed, which have the same results as above.