[Problem/Bug]: WebView2 on UWP doesn't support multi-instance app

[aquinn39]

What happened?

Copied from here: microsoft/microsoft-ui-xaml#6253.
As Microsoft is no longer fixing most WinUI 2 bugs, this is not going to be fixed in WinUI 2 appearantly. I am filing this here to see if this is something that can be looked at by the WebView2 team and fixed in the WebView2 package instead of WinUI.

Importance

Important. My app's user experience is significantly compromised.

Runtime Channel

Stable release (WebView2 Runtime)

Runtime Version

120.0.2210.77

SDK Version

1.0.2151.40

Framework

WinUI2/UWP

Operating System

Windows 11

OS Version

22621.2861

Repro steps

1. Create a UWP project
2. Install WinUI 2, which provides WebView2
3. Add a WebView2 to MainPage
4. Change package.appxmanifest to support multi-instance
5. Launch app (first instance)
6. Launch app again (second instance)
7. Close app window that launched at 5.

See microsoft/microsoft-ui-xaml#6253 for video of issue.

Repros in Edge Browser

No

Regression

No, this never worked

Last working version (if regression)

No response

[champnic]

Hey @aquinn39 - Unfortunately we won't be able to fix this either. The issue is on the WinUI2 side and they own building and shipping the WinUI2 version of WebView2.