Remove treble clef from Custom Key Signatures Creator
In Master palete -> Key Signatures -> Create Key Signature
there is a treble cleff, which has no music function "Note: The treble clef is only decorative - custom key signatures for any type of staff can be created here." and is only confusing many users.
It would be better, to remove this "decorative" cleff from there, until transpositions for custom key signatures will be added (if ever it is plan, to do that).