*blink blink* Uh... what?
EDIT: Okay... Cave Editor is famous for being incompatible with Sue's Workshop, right? That is, after editing with Cave Editor you can no longer edit with Sue's Workshop? The question is: would you consider fixing that?
If the answer is "no", then I have an alternative suggestion: have both Cave Editor and Sue's Workshop put something in a fixed location in the executable which indicates that it has been edited with that respective program. Then if Sue's Workshop finds Cave Editor's magic word in the file, it will know that it cannot edit it; similarly, if Cave Editor finds Sue's Workshop's magic word in the file, it will know that it cannot edit it (if that's the case, at least) or alternatively that it has to read it slightly differently.