Currently, the preview pane (on the right side) shows the live form, and as you make changes to CSS/JS and save them, it updates that view.

The problem is that the HTML markup of the stored form can be drastically different than that of the live form, which causes CSS/JS to break in unpredictable ways.

It would be great if we could switch between "live" and "post-submission" previews of the form. That would eliminate the need to fill out and submit forms over and over just to fiddle with the look-and-feel of the form.