### 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
switch (current_menu_option) {
		case FILE_NEW_INHERITED_SCENE: {
			Node *scene = editor_data.get_edited_scene_root();
			
			if (!scene) {
				_menu_option_confirm(FILE_CLOSE, true);
			}
			load_scene(p_file, false, true);
		} break;
		case FILE_OPEN_SCENE: {
			load_scene(p_file);
		} break;
		case SETTINGS_PICK_MAIN_SCENE: {
			ProjectSettings::get_singleton()->set("application/run/main_scene", p_file);
			ProjectSettings::get_singleton()->save();
			
			project_run_bar->play_main_scene((bool)pick_main_scene->get_meta("from_native", false));
		} break;
		case FILE_CLOSE:
		case SCENE_TAB_CLOSE:
		case FILE_SAVE_SCENE:
		case FILE_SAVE_AS_SCENE: {
			int scene_idx = (current_menu_option == FILE_SAVE_SCENE || current_menu_option == FILE_SAVE_AS_SCENE) ? -1 : tab_closing_idx;
			if (file->get_file_mode() == EditorFileDialog::FILE_MODE_SAVE_FILE) {
				bool same_open_scene = false;