Submit buttom on free form question in quizmaker '13

Hi

I've created the attached exercise with Quizmaker '13 using the freeform.

The exercise consists in dragging the 4 blu boxes on the left to the empty boxes on the right.

The "submit" button ("Invia") is visible from the beginning while I would like it to appear ONLY when the four items have been dragged.

Is that possible?

Thanks