### 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 (vcs_actions_menu->get_item_id(p_idx)) {
		case RUN_VCS_METADATA: {
			VersionControlEditorPlugin::get_singleton()->popup_vcs_metadata_dialog();
		} break;
		case RUN_VCS_SETTINGS: {
			VersionControlEditorPlugin::get_singleton()->popup_vcs_set_up_dialog(gui_base);
		} break;
	}
}
void EditorNode::_update_title() {
	const String appname = GLOBAL_GET("application/config/name");
	String title = (appname.is_empty() ? TTR("Unnamed Project") : appname);
	const String edited = editor_data.get_edited_scene_root() ? editor_data.get_edited_scene_root()->get_scene_file_path() : String();
	if (!edited.is_empty()) {
		
		title = vformat("%s - %s", edited.get_file(), title);
	}
	if (unsaved_cache) {
		
		title = vformat("(*) %s", title);
	}
	DisplayServer::get_singleton()->window_set_title(title + String(" - ") + VERSION_NAME);
	if (project_title) {
		project_title->set_text(title);
	}
}
void EditorNode::shortcut_input(const Ref<InputEvent> &p_event) {