Winforms: 'File name' ComboBox in SaveFileDialog is truncated by default after clicking 'Hide Folders'

[Olina-Zhang]

• .NET Core Version:
  5.0.100-preview.8.20363.2 from master branch

• Have you experienced this same bug with .NET Framework?:
  Yes

• More info:
  This is not a regression issue, can repro in .Net Core previous version and .Net framework

Problem description:
'File name' ComboBox in SaveFileDialog is truncated by default after clicking 'Hide Folders'. After resizing this dialog, truncation will be resolved. See following screenshot:

Expected behavior:
No truncation in SaveFileDialog

Minimal repro:

1. Create a Winforms .Net Core app
2. Add a SaveFileDialog to the form designer
3. Write one line code to show SaveFileDialog when running app
4. Build and run this app
5. In SaveFileDialog, click 'Hide Folders', and then observe 'File name' comboBox

Or

1. Extract following attached project and open it
   WindowsFormsApp20.zip
2. Build and run this app, in SaveFileDialog, click 'Hide Folders', and then observe 'File name' comboBox

[Tanya-Solyanik]

This is a native dialog, this overlap repros in notepad as well:

[RussKie]

@Olina-Zhang this is a Windows dialog, we don't own it. I suppose you can raise an AzDO ticket to the Windows team.