The SQL Tab allows you to get a closer look at the SQL script of your View.
You can see the SQL script that was created using the Wizard.
You can write you own Custom WHERE clause if needed.
If there already a WHERE clause your custom SQL will be appended to the Wizard SQL.
If there is not a WHERE clause one will be created for you.
If the Wizard could not fullfill all of your requirements you can enter Manual Edit mode by checking 'Manually Edit View'.
Upon checking 'Manual Edit View' you will be alerted to the fact that entering Manual Edit mode cannot be undone and will disable the Wizard Tab.
At this point can can click 'OK' to continue or 'Cancel' to not enter Manual Edit Mode.
If you choose to continue you can also delete any references to the View by checking 'Delete all references to this View'.
Now that Manual Edit mode has been enabled the Additional Where Clause has been added to the main body of the SQL script.
All subsequent alterations to this View must now be made directly to the SQL as the Wizard Tab has been disabled.