Popup element are reversed left and right in Windows 11

[ChengYen-Tang]

• .NET Core Version: .net 5~6(e.g. 3.0 Preview1, or daily build number, use dotnet --info)
• Windows version: Windows 11
• Does the bug reproduce also in WPF for .NET Framework 4.8?: Yes/No
• Is this bug related specifically to tooling in Visual Studio : No
• Security issues and bugs should be reported privately, learn more via our responsible disclosure guidelines.

Problem description:
I found that using the Popup element and setting the Placement to left will actually appear on the right and the right will appear on the left
This problem happens on windows 11, windows 10 is normal
Note: Visual studio menu also has this problem

Actual behavior:
Windows 11:

Expected behavior:
Windows 10:

Minimal repro:

[lindexi]

It's looks like a Windows problem, not the WPF issues.

[ChengYen-Tang]

Seems yes, but I have a few questions

1. This problem has existed since the release of Win11, but it has not been improved
2. My colleagues use Qt to develop desktop applications, this problem does not appear in Qt
3. I have been using Win11 for a while, and most programs do not have this problem
4. I don't know how to give feedback to the windows department

[miloush]

I believe this works as designed. There is a setting in Windows that controls on which side the menu appears.

This used to be part of Control Panel > Table PC settings > Other tab > Handedness.

However, I no longer have this tab on Win11. Try Settings > Bluetooth & Devices > Pen & Windows Ink > Choose which hand you write with.

The corresponding registry setting should be HKCU\Software\Microsoft\Windows NT\CurrentVersion\Windows\MenuDropAlignment.

[singhashish-wpf]

Thanks @miloush!
@ChengYen-Tang Please close the issue if the above answer helped, Let us know in case there is something more to it.

[ChengYen-Tang]

Hi @singhashish-wpf
I think @miloush just provides a temporary solution to the problem.
I can't ask all Windows 11 users to set the registry.
In my project, because the left and right are reversed, the layout is severely shifted.

[miloush]

@ChengYen-Tang I am implying this is not a WPF issue. It's a global OS setting and any Windows 11 user can set it the way the prefer.

[lindexi]

@ChengYen-Tang How about we edit the register?

HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Windows\MenuDropAlignment

• Value 0 : Default, Left-handed
• Value 1 : Right-handed

After you edit the value, you need to sign out and sign in back to your Windows account or restart your computer. Windows should place the context menu on the right side.

See https://www.top-password.com/blog/tag/tablet-pc-settings-windows-10/

[ChengYen-Tang]

@lindexi ,
It works, but the default in Windows 11 is 1.

[lindexi]

@lindexi ,

It works, but the default in Windows 11 is 1.

Sorry,my Windows is 0