I too have an issue with the Draggable Proof problem.
Below is a re-posting of the problem posted 6 weeks ago:
For those interested in using the draggableProof.pl macro there seems to be a small glitch in that phrase segments are duplicated upon revisiting the problem after the initial attempt.
We are using an MAA subscription Version 2.13.
When a draggable proof problem is attempted, the chosen phrase segments from the left column are dragged to the right column where the complete "Proof" is formed. Regardless of whether the answer is correct or incorrect, and regardless of whether the phrase segments chosen come from the pool of "correct" phrases or from the pool of "false" phrases, duplication will result in all phrase segments that have been left in the right hand column.
To recreate the duplication error you must leave phrase segments in place in the right hand column, then leave the problem and perhaps open another problem and then return to the draggableProof problem. Upon your return one should find all the chosen selections on the right column duplicated in the left column. It is as if the problem needs to be "reset" upon re-opening and not hold the previous efforts.
One can continue with this duplication scheme and create triples and quadriples of singular phrases. But of course this is not the intention of the problem.