### Godot version

4.1.1

### System information

linux

### Issue description

[simplescreenrecorder-2023-08-30_15.01.51.webm](https://github.com/godotengine/godot-proposals/assets/71937306/537d92b9-4f98-4fe6-adf4-71297be0471a)

I guess this wasn't the case before since I could save a layout named "2 monitors".

### Steps to reproduce

press space

### Minimal reproduction project

none
EditorNode::get_singleton()->edit_resource(p_resource);
}
void ThemeTypeEditor::_font_item_changed(Ref<Font> p_value, String p_item_name) {
	EditorUndoRedoManager *ur = EditorUndoRedoManager::get_singleton();
	ur->create_action(TTR("Set Font Item in Theme"));
	ur->add_do_method(*edited_theme, "set_font", p_item_name, edited_type, p_value.is_valid() ? p_value : Ref<Font>());
	if (edited_theme->has_font(p_item_name, edited_type)) {
		ur->add_undo_method(*edited_theme, "set_font", p_item_name, edited_type, edited_theme->get_font(p_item_name, edited_type));
	} else {
		ur->add_undo_method(*edited_theme, "set_font", p_item_name, edited_type, Ref<Font>());
	}
	ur->add_do_method(this, "call_deferred", "_update_type_items");
	ur->add_undo_method(this, "call_deferred", "_update_type_items");
	ur->commit_action();
}
void ThemeTypeEditor::_icon_item_changed(Ref<Texture2D> p_value, String p_item_name) {
	EditorUndoRedoManager *ur = EditorUndoRedoManager::get_singleton();
	ur->create_action(TTR("Set Icon Item in Theme"));
	ur->add_do_method(*edited_theme, "set_icon", p_item_name, edited_type, p_value.is_valid() ? p_value : Ref<Texture2D>());
	if (edited_theme->has_icon(p_item_name, edited_type)) {
		ur->add_undo_method(*edited_theme, "set_icon", p_item_name, edited_type, edited_theme->get_icon(p_item_name, edited_type));
	} else {
		ur->add_undo_method(*edited_theme, "set_icon", p_item_name, edited_type, Ref<Texture2D>());
	}
	ur->add_do_method(this, "call_deferred", "_update_type_items");
	ur->add_undo_method(this, "call_deferred", "_update_type_items");
	ur->commit_action();
}
void ThemeTypeEditor::_stylebox_item_changed(Ref<StyleBox> p_value, String p_item_name) {