clipboard.ClipboardText always return null when copy in notepad

[Yiming075]

I meet a bug while using the clipboard.ClipboardText. It works in some cases but not in the notepad. I am using Windows 10 and vs2022

Here is the code to reproduce the error

The bug demo video

[Willy-Kimura]

Have you tried testing with other applications?
Also is the demo having the same behavior from your end?