Once you fill in the Expression Assistant fields, you can preview how the Interaction Wizard UI, along with the generated code, will look by clicking the Preview button to display the information in the Expression Preview window.
For example, if you enter the following in the Expression Assistant,
clicking the Preview button displays the following in the Expression Preview window:
You can experiment with the value and see what it generates by clicking on the Update Code button. To close the Expression Preview window, click its Close button.
When you are finished modifying the expression in the Expression Assistant, click OK to return to the Interaction Wizard Editor.