When executing a query the data is returned to the script output instead of the data grid.
This is because of hitting the incorrect execute button to display data in data grid.
In Toad there are two ways to execute a script, as a statement or as a script. When running a single statement you can run as a script or a statement. When running multiple statements you must run as a script. When running as a statement the data returns to the data grid. When running as a script the data returns to the script output tab. In order to return data to the data grid, the query must be run as a statement.
Run as Statement: Green arrow icon on sql editor window (Also F9)
Run as Script: Lightening bolt icon on sql editor window (Also F5)