How to remove the flickering of WinUI3 windows on startup and shutdown

[MrJone2457]

Describe the bug

When I developed a WinUI3 screenshot application, I found a problem that I hadn't noticed before,
When the WinUI3 application starts and closes, if the system is the light theme, the flashing is white, and the visual effect is obvious. If the system is the black theme, the flashing is black. This problem may be related to this #5148 issue is somewhat related, but there seems to be no solution to this issue at present.

The application is launched in full screen mode, and the application interface displays a screenshot of the desktop.I personally want the effect to be as clean as the startup effect of the win11 Snipping Tool, or I can set the startup effect of fading in, and it is best to be clean and not flickering when it is closed. Is there any way?
Reference code https://github.com/MrJone2457/ScreenShot

Steps to reproduce the bug

Reference code
https://github.com/MrJone2457/ScreenShot

Expected behavior

No response

Screenshots

https://twitter.com/i/status/1589994651263852544
https://twitter.com/i/status/1590004799248171008
Don't know how to upload videos on github, check the video link on Twitter

NuGet package version

WinUI 3 - Windows App SDK 1.1.5

Windows app type

• UWP
• Win32

Device form factor

Desktop

Windows version

Windows 11 (22H2): Build 22621

Additional context

No response

[github-actions]

This issue is stale because it has been open 180 days with no activity. Remove stale label or comment or this will be closed in 5 days.

[garrettpauls]

This is still an issue we're seeing as of WindowsAppSDK version 1.4.231219000, please consider reopening this.

It's difficult to create a small app that reproduces it reliably, but in our control-heavy business application it's pretty clear that the main Window is being shown before the content is loaded, which causes a bright white flicker before our darker UI loads (not theme dark, just darker than the default control theme).

It seems like a reasonable solution to this would be to not make the Window visible until the content has loaded and done a single render pass, but I don't know if that's an easy change to make internally. I'd be happy to use that as a workaround if there was a way to do that from an app implementation standpoint, but I haven't been able to find a way to trigger the controls to render before the Window becomes visible.