If I run 4.2 + version, fullscreen on macOS, the menu bar will automatically disable or hide after saving by pressing command + S, and the tscn file will crash sometimes when I reopen or reload the project, I have to delete and recover it to read the origin file. And, the function get_tree().change_scene_to_packed() or other change scene function will leave a blank between changing scenes, it never happened in 4.1 version or before.
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If I run 4.2 + version, fullscreen on macOS, the menu bar will automatically disable or hide after saving by pressing command + S,
This is a known issue: The menu bar stops appearing after saving in the fullscreen editor on Mac · Issue #86495 · godotengine/godot · GitHub
get_tree().change_scene_to_packed() or other change scene function will leave a blank between changing scenes, it never happened in 4.1 version or before.
This is due to changes performed in the change_scene_to_{file,packed}() implementation to make it more optimal and predictable. I suggest adding a loading plaque in the form of a TextureRect or ColorRect node that you display a frame before calling that method to hide the transition. In general, you want to ensure you always have some kind of loading text visible when loading occurs.