Jump on going from stack to substack

[Stgoldberg at aol.com]

I've noticed that when going from one card in the main stack to another card  
 in the same stack the transition is smooth.   However, when going from the 
main stack to a card in a substack there is a brief "flash" showing one stack 
closing and the other opening.   This does not seem to be resolved by setting 
the lockscreen to true.   The nature of the script is as follows:

on mouseUp
  go to card 2 of stack "gross" -- from stack "Pathology museum"
  close stack "Pathology museum" -- so the two stacks cannot both exist on 
the screen if the user moves a stack around 
end mouseUp

It's not a major problem, but would look better without the jump.   Any 
suggestions?   Thanks.
Steve Goldberg