The Last Saved Command
You can use the Cancel 
and Check 
buttons at the top of the Assistant tab to save the command and display it in the Source tab. You can make further changes to the command, and if you don't save them, you can restore the last saved command if required.
For example:
1. Save the command that has just been entered by clicking on the check button. The saved command is displayed at the top of the Command Assistant.
2. Delete the #SURNAME field from the Fields parameter:
3. Press the Cancel button. The command reverts to the last saved format:
