function get_error_level() {
		// calculate level in case global errors have been cleared
		$e = 0;
		foreach( $this->err_stack as $t => $ids ) {
			foreach( $ids as $id ){
				$Err = PLUGError::get_reference( $t, $id );
				if( is_object($Err) ){
					$e |= $t;
					break;
				}
			}
		}
		return $e;
	}