Shared databases are databases which are sent to all Design Studio clients being activated by (getting license from) the Management Console. To simplify the user interface, these databases are configured on a cluster. So in order for the databases available in a certain cluster to also be available to Design Studio clients, simply select the cluster here. If one desires to have a special set of databases available for Design Studio (for instance, maybe one is not interested in having production databases sent to Design Studio) a special Design Studio cluster can be created on which the shared databases are defined. The default cluster for shared databases is the default, and automatically created, Production cluster.