### 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
if (!p_tree_item->get_meta("_can_be_imported")) {
		return;
	}
	TreeItem *data_type_node = p_tree_item->get_parent();
	if (!data_type_node || data_type_node == import_items_tree->get_root()) {
		return;
	}
	TreeItem *type_node = data_type_node->get_parent();
	if (!type_node || type_node == import_items_tree->get_root()) {
		return;
	}
	ThemeItem ti;
	ti.item_name = p_tree_item->get_text(0);
	ti.data_type = (Theme::DataType)(int)data_type_node->get_metadata(0);
	ti.type_name = type_node->get_text(0);
	if (!selected_items.has(ti)) {
		p_tree_item->set_checked(IMPORT_ITEM, false);
		p_tree_item->set_checked(IMPORT_ITEM_DATA, false);
		return;
	}
	if (selected_items[ti] == SELECT_IMPORT_FULL) {
		p_tree_item->set_checked(IMPORT_ITEM, true);
		p_tree_item->set_checked(IMPORT_ITEM_DATA, true);
	} else if (selected_items[ti] == SELECT_IMPORT_DEFINITION) {
		p_tree_item->set_checked(IMPORT_ITEM, true);
		p_tree_item->set_checked(IMPORT_ITEM_DATA, false);
	}
}
void ThemeItemImportTree::_update_total_selected(Theme::DataType p_data_type) {