[Bug]: File Pickers just do not work

[gentledepp]

Version

Win 11
I guess the latest app isioation version? (How should I know?)

Repro Steps

Launch my repro app: WpfPackaged
It is a WPF app that tries to show a filepicker to the user.

Following the documentation I managed to get it to the point where:

• the file open dialog opens and does not show an "Access denied" messagebox all the time

• but when the user selects e.g. a jpg file and klicks "ok", then the dialog returns with a result true but the FileName is empty...

this has to be a bug.

Unexpected Results

[Rybasum]

The same happens with WinAppSDK 1.8 and 2.0 when running in AppContainer. Microsoft fixed file pickers when running as Administrator but not when sandboxed.