Liv-Goh
Liv-Goh
Verified this issue on 9.0.100-preview.6.24312.9 with dlls built from winforms repo of main branch, it was fixed: the tree nodes added by using TreeNodeCollection.AddRange are sorted correctly 
Verified this in .NET 9.0.100-preview.7.24323.5, the binary formatter issue on image list unable to fix by adding codes above to the .csproj file.
@elachlan the test results are as below > * What is the value of the HelpNamespace in the designer.cs? HelpNamespace value is empty string in both .NET 8 and 9...
@SimonZhao888 Yes, the error exception will pop out after change the exception setting and set 'Enable Just My Code' to disable 
Encounter the same issue on WinForms Application Form.Designer.cs file using VS Version 17.11.0 Preview 2.0. Need to set VS theme to dark mode to repro this issue.
Verified this issue on the latest .NET 9.0.100-preview 6.24320.9, this issue still repro. Narrator:  NVDA: 
When a ComboBox's data source is bound to an ImmutableArray, its value is reset when it loses focus.
@elachlan The issue can reproduce on both .NET Framework from 4.6 - 4.8.1 and .NET from 6.0 - 9.0. 
Verified the issue with .NET 9.0.100-preview7.24402.8 test pass build that the issue has been fixed, which have the same results as above.