The SViewport obtained by GetGameViewportWidget cannot be embedded into other windows

Development Programming & Scripting
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1

TSharedPtr DefaultRootWindow = GEngine->GameViewport->GetWindow();
DefaultRootWindow->HideWindow();
TSharedPtr WindowPtr = SNew(SWindow);
WindowPtr->SetContent(GEngine->GameViewport->GetGameViewportWidget().ToSharedRef());

The code can run normally in version 5.4, but after upgrading to 5.5, the same code cannot display content in the viewport, only a black area