Scratch

I am getting very stuck when trying to make my Pyramid Solitaire simulation, because of a glitch, and I've already asked a very good programmer and he has said he can't help, he can't crack it either.

Go to this project.
Click the deck in the lower-right.
The game will now deal. Wait until it is finished.
Now click the deck in the top-left.
A new card should deal to the discard pile, however, it moves straight back to the deck as though it was never there after 0.2 seconds. What should happen is the card is stamped there, then the deck returns to the top-left.

The script in use is a script towards the centre-right of the scripting area of the sprite 'Deck'. Can you download it and see if you can spot what I've done wrong?

NOTES:
I am aware you can only pick up the cards on the bottom-row, the others haven't been programmed yet.
If you go to the Settings menu by clicking the spanner, you can view the instructions, but don't change any of the changeable settings, because they aren't programmed yet.