With _CrvDeviation, when the 2 objects are selected, I get a strange prompt:

EDIT:
Ah, now I understand.
It’s a hint for what Rhino expects.
Good idea, but confusing…
E.g. when _Rotate asks for angle or 1st reference, the hint reads “Punkt oder Nummer” (point or number).
“Punkt oder Zahl” would be better.