Selecting a line, going to that card

[Scott Pepperdine]

Thanks to help received on this list, I now have a list field that 
contains the names of all the cards in that stack. I'd like the user to 
be able to double click on a line and go to that card.  I've tried 
variations on the following without success.:
  on mousedoubleup
    put the selectedline into tNewCard
    go to card tNewCard
end mousedoubleup

Probably simple again.  Thanks for any help.