Security: the order of child should be correct if the child nodes are readable.

If access rights are set such that a session can read child nodes of a node, then that session should also be able to read the child nodes in the right order (for orderable nodes). Even if the session does not have permission to read the properties of a node.

The order of child nodes is stored in a hidden property. Access rights for this hidden property are currently checked in the same way as access rights for regular properties.