Child windows drop to 1 FPS they obscure their parent [Wayland/Mutter]

[santiagocezar]

Godot version

v4.0.beta7.official [0bb1e89fb]

System information

Arch Linux, GNOME Wayland 43.2, Intel UHD Graphics 620, Mesa 22.2.3

Issue description

Child windows seem to be frame limited when covering their parent window. This is caused by GNOME Mutter window culling, which prevents unnecesary redraws for windows that are not visible.

Grabación de pantalla desde 2022-12-11 16-17-23.webm

This also happens when clicking Browse in that dialog, because it opens the file picker which covers it instantly.

Steps to reproduce

1. Open the Project Manager
2. Click on "New Project"
3. Resize the window so it covers the Project Manager
   (or alternatively, click the browse button)
4. Interact with new child window

Minimal reproduction project

N/A