User Experience:
Users who rely on screen reader will not be able to get the info of sub menu if role/state is not provided properly

Test Environment:
App: Windows Terminal Preview
Feature: Command Palette
Screen Reader: Narrator
OS: Win 10 2004 Build (19041.508)

Repro Steps:
1.Open Windows terminal Preview app
2.Open Command Palette using shortcut (Ctrl+shift+p)
3.Search for New tab command in the search field
4.Navigate to New Tab list item having sub menu and Observe whether screen reader is providing proper info or not

Actual:
Screen reader user will not be able to identify the purpose of New Tab control if role and state are not appropriate. Screen reader announces the name and position only and also Multiple New tab list items are present in the list and the announcement is same which will confuse user.

Note: Same issue repro for Split pane and Set color scheme controls having Sub menu

Expected:
State should announce state as Collapsed or it should provide extra role description like "Has pop Up" which helps in differentiating the New tab list items and also the purpose of New tab having sub menu.

MAS Reference:
https://microsoft.sharepoint.com/teams/msenable/_layouts/15/WopiFrame.aspx?sourcedoc={248054a6-5e68-4771-9e1e-242fb5025730}