### 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
exiting = true;
	resource_preview->stop(); 
	_save_editor_layout();
	
	dim_editor(true);
	get_tree()->quit(p_exit_code);
}
void EditorNode::_discard_changes(const String &p_str) {
	switch (current_menu_option) {
		case FILE_CLOSE:
		case SCENE_TAB_CLOSE: {
			Node *scene = editor_data.get_edited_scene_root(tab_closing_idx);
			if (scene != nullptr) {
				String scene_filename = scene->get_scene_file_path();
				if (!scene_filename.is_empty()) {
					previous_scenes.push_back(scene_filename);
				}
			}
			
			if (!_is_closing_editor()) {
				_remove_scene(tab_closing_idx);
				_update_scene_tabs();