Opening the "settings://" protocol causes the WinUI3 application to crash

[stefanvd]

Describe the bug

I have 2 WinUI3 applications in a 1 package project, both with protocol schemes such as "settings" and "main" (=set default project in the package). However, when I try to open the protocol using the Run window with "settings://", it crashes.

The error message:

Exception thrown: 'System.Runtime.InteropServices.COMException' in WinRT.Runtime.dll
WinRT information: The Application Object must initially be accessed from the multi-thread apartment.
An unhandled exception of type 'System.Runtime.InteropServices.COMException' occurred in WinRT.Runtime.dll
WinRT information: The Application Object must initially be accessed from the multi-thread apartment.
The application called an interface that was marshalled for a different thread.

Steps to reproduce the bug

1. Download https://github.com/stefanvd/winui3protocol
2. Open Visual Studio "main" project
3. Run the "package" on (ARM64)
4. The "main" window shows up. Then when you open the "Run" window (windows+ R) and type "settings://hello". It crashes instead of displaying the "settings" window as it should

Expected behavior

4. Open the "Settings" window

Screenshots

No response

NuGet package version

WinUI 3 - Windows App SDK 1.3.3: 1.3.230724000

Windows version

Windows Insider Build (xxxxx), Windows 11 (22H2): Build 22621

Additional context

See this discussion microsoft/WindowsAppSDK#3795 (reply in thread)