After running a query, the results are displayed in the grid. It is set to fetch only the first n records (Toad Option setting). The records are displayed as expected but the duration counter is still counting as if the query is still running.
It continues forever and never finishes.
The duration noted here is not the same as the execution/run time it takes for the query itself.
Once the process is stopped, the execution/run time will display.
To stop the process, open the background process window and cancel it. Or scroll to the end of the result set in the grid.
To check the execution/run time without fetching all the data or stopping the process, go to the Messages tab and check for the run time.
The background process is left open because it may potentially fetch more records. This is only an issue when the "Number of rows to initially fetch" option is enabled and not set to "unlimited". This is found under Tools | Options | Database | General and Oracle.