I would find it really helpful to be able to search through all my lessons in a particular file to find a particular flashcard, rather than having to manually scan the 'edit' list for each lesson.
Thanks.
This feature is available in the new Stackz 07 beta!
With the "Wordlists - Find Stackz Wordlists..." menu command you can find wordlists containing a certain text.
EDIT:
I guess I missunderstood the question, and the above hint is not addressing your issue.
But you can edit all stacks, and then search a certain text there.