[Accessibility] Inconsistent display order of TabPage pane in the UIA tree

[MelonWang1]

.NET version

.NET 9.0.100-alpha.1.23564.26

Did it work in .NET Framework?

Yes

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

Yes, this issue cannot repro in .NET 3.1/5.0, can repro in .NET 6.0/7.0/8.0.

Issue description

Actual result: The TabPage1 pane is at the bottom of more/less buttons.

Expected result: The TabPage1 pane should be on the top of the more/less buttons.

Steps to reproduce

1. Create a Winforms .NET Core application
2. Add a TabControl
3. Add some tab to see more/less buttons
4. Build and run
5. Open Inspect or Accessibility Insights tool
6. Focus on TabPage1 pane

[Epica3055]

@lonitra @Tanya-Solyanik I need some help.

When I tried to change winfrom main branch to 5.0, since the issue says that 5.0 works fine, and I tried to execute Restore.cmd , it showed some errors. So how can I run 5.0?

E:\winforms>Restore.cmd
Processing E:\winforms\global.json
cmake.exe already exists; replacing...
dotnet-api-docs_net5.0 was not found in .
Native tools bootstrap failed
MSBUILD : error MSB1001: Unknown switch.
Switch: -NativeToolsOnMachine

For switch syntax, type "MSBuild -help"
Build failed.

[Tanya-Solyanik]

@MelonWang1 - could you please share where you installed NET5 from?

[MelonWang1]

@Tanya-Solyanik I'm using .NET 5.0(5.0.17) that comes with VS.

[Tanya-Solyanik]

@Epica3055 - FYI - https://github.com/dotnet/winforms/issues/4120 might or might not have a similar root cause

[Epica3055]

@Tanya-Solyanik thank you for the lead.

[JeremyKuhne]

Fallout from introducing our own UIA provider. No known way to solve, but there are workarounds for test. (Per @Tanya-Solyanik)