[3.1rc1] Monitoring / Show MySQL Database size

Clicking on Monitoring -> "Show MySQL Database size" creates mysql-query errors:

14.09.2016 10:50		Warning	[INTERFACE]: Falsche Anfrage / Wrong QuerySQL-Query = SELECT domain FROM web_domain WHERE domain_id=(SELECT parent_domain_id FROM web_database WHERE database_name='c8cms' -> 1064 (You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '' at line 1)

There is a missing ")" at the end of the query.