Remove space fails with a SQL Integrity Contraint Violation

Cause:
org.springframework.dao.DataIntegrityViolationException: (HibernateTemplate): data integrity violated by SQL 'null'; nested exception is java.sql.SQLException: Integrity constraint violation: FK6382C059598614D0 table: CONTENT in statement [delete from SPACES where SPACEID=3]

Stack Trace: [hide]

org.springframework.dao.DataIntegrityViolationException: (HibernateTemplate): data integrity violated by SQL 'null'; nested exception is java.sql.SQLException: Integrity constraint violation: FK6382C059598614D0 table: CONTENT in statement [delete from SPACES where SPACEID=3]
java.sql.SQLException: Integrity constraint violation: FK6382C059598614D0 table: CONTENT in statement [delete from SPACES where SPACEID=3]
at org.hsqldb.Trace.getError(Unknown Source)
at org.hsqldb.jdbcResultSet.(Unknown Source)
at org.hsqldb.jdbcConnection.executeStandalone(Unknown Source)
at org.hsqldb.jdbcConnection.execute(Unknown Source)
at org.hsqldb.jdbcStatement.fetchResult(Unknown Source)
at org.hsqldb.jdbcStatement.executeUpdate(Unknown Source)
at org.hsqldb.jdbcPreparedStatement.executeUpdate(Unknown Source)
at net.sf.hibernate.impl.NonBatchingBatcher.addToBatch(NonBatchingBatcher.java:22)
at net.sf.hibernate.persister.EntityPersister.delete(EntityPersister.java:598)
at net.sf.hibernate.impl.ScheduledDeletion.execute(ScheduledDeletion.java:29)
at net.sf.hibernate.impl.SessionImpl.executeAll(SessionImpl.java:2382)
at net.sf.hibernate.impl.SessionImpl.execute(SessionImpl.java:2340)
at net.sf.hibernate.impl.SessionImpl.flush(SessionImpl.java:2204)
at net.sf.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:61)