### Godot version

4.1 rc3

### System information

Windows 10.0.19045 - Vulkan (Forward+) - dedicated NVIDIA GeForce GTX 1060 (NVIDIA; 30.0.15.1403) - Intel(R) Core(TM) i7-7700HQ CPU @ 2.80GHz (8 Threads)

### Issue description

This™
![image](https://github.com/godotengine/godot/assets/2223172/cb33110f-a5b0-400a-951f-3fa425f05714)

It can still happen, but it's more difficult to trigger.

### Steps to reproduce

1. Create a new scene with a Control node
2. Add Theme to the Control
3. Open Theme Editor
4. Clear the `theme` property in Control
5. Save, with Theme Editor opened
6. Restart

### Minimal reproduction project

N/A
case HELP_COMMUNITY: {
			OS::get_singleton()->shell_open("https:godotengine.org/community");
		} break;
		case HELP_ABOUT: {
			about->popup_centered(Size2(780, 500) * EDSCALE);
		} break;
		case HELP_SUPPORT_GODOT_DEVELOPMENT: {
			OS::get_singleton()->shell_open("https:godotengine.org/donate");
		} break;
		case SET_RENDERER_NAME_SAVE_AND_RESTART: {
			ProjectSettings::get_singleton()->set("rendering/renderer/rendering_method", renderer_request);
			ProjectSettings::get_singleton()->save();
			save_all_scenes();
			restart_editor();
		} break;
	}
}
String EditorNode::adjust_scene_name_casing(const String &root_name) {
	switch (GLOBAL_GET("editor/naming/scene_name_casing").operator int()) {
		case SCENE_NAME_CASING_AUTO:
			
			break;
		case SCENE_NAME_CASING_PASCAL_CASE:
			return root_name.to_pascal_case();
		case SCENE_NAME_CASING_SNAKE_CASE:
			return root_name.replace("-", "_").to_snake_case();
	}
	return root_name;
}
void EditorNode::_request_screenshot() {