Changing Window.borderless property causes main window to vanish on macOS

[BrixsterPlanet]

Godot version

4.2.dev4.mono.official [549fcce]

System information

Godot v4.2.dev4.mono - macOS 14.0.0 - Vulkan (Forward+) - integrated Apple M2 - Apple M2 (8 Threads)

Issue description

Note: This issue was discovered on the Mono version of Godot, but it may not be related to the Mono build itself. Additional testing on the vanilla build and other operating systems might be necessary to understand the scope of the problem entirely.

I'm using Godot to create a non-game application. I currently have a borderless splash screen that changes to a regular window when the main application scene is loaded.

Right now, changing the borderless property at runtime causes the window to just... disappear?

Screen.Recording.2023-09-25.at.8.20.40.PM.mov

The project itself runs fine, and the script logic will execute perfectly normally, but the window itself is not present to render anything.

Additionally, it should be noted that the window is not invisible. It does not show up in my window manager at all. Mission Control treats my application as being run in the background due to having no visible window.

Steps to reproduce

At runtime, programmatically change the main window's borderless property:

 get_viewport().get_window().borderless = true

C#:

GetViewport().GetWindow().borderless = true

This may only be an issue with Mac. I will perform additional testing on my Windows build to see if it causes problems there.

Minimal reproduction project

N/A. This was successfully reproduced on a brand new project with a single script:

extends Node3D

# Called when the node enters the scene tree for the first time.
func _ready():
	get_viewport().get_window().borderless = true

Keep in mind that this might only be an issue on macOS. Specifically, I am on the Sonoma developer beta, so this could be a bug with macOS itself. However, setting borderless in the project settings has worked perfectly fine so I felt confident enough to report this as an issue, as it's been heavily messing with my work.