Yes, this is fully supported. The GUI only ‘transfers’ a load test job to a local or to a remote Exec Agent (load generator), which allows you to execute an unlimited number of parallel load test jobs at the same time. Each Exec Agent is also able to execute several load test jobs at the same time. Nevertheless, the GUI can (but doesn't have to) hold a live network connection to each load test job which allows to display real time statistics. Closing a real time statistic window will not interrupt a load test job.