Starting from runtime version 139, the restart button at (bottom right) page edge://flags behiavor is changed

[jls28]

Starting with WebView2 Runtime version 139,
the behavior of the Restart button
(located at the bottom-right of the edge://flags page)
when a flag is modified,
(and the edge://quit page behiavor) has changed significantly:

• These actions now immediately terminate the application by sending a WM_CLOSE message.
• If the WM_CLOSE message is ignored, a ProcessFailed/UNEXPECTED event is triggered.
• Unfortunately, it's not possible to distinguish whether the WM_CLOSE was sent by WebView2, making it impractical to handle gracefully.

Prior to Version 139:

• The Restart button and edge://quit page would only trigger a ProcessFailed/UNEXPECTED event, allowing the application to respond appropriately.

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I believe this new behavior is problematic for most applications.
The previous approach used in WebView2APISample was more user-friendly: it prompted the application to recreate the WebView window rather than abruptly terminating it.
Now, the application is closed without warning or explanation, which can lead to a poor user experience.