Add Datasource dialog spinning forever regardless of the success

Steps to reproduce:

• Add a non-XA h2 datasource with name t1, class asadasdasdsa and jdbc:h2:mem:test;DB_CLOSE_DELAY=-1;DB_CLOSE_ON_EXIT=FALSE
• Click finish whatever the last confirmation button name is
• Expected: the spinner spins for some time and the dialog is closed upon success
• Found: the spinner spins forever and the dialog stays open. When I close the dialog manually, the new t1 datasource is there in the list