[racket] Couldn't find a step matching that criterion

I am having a real issue with the stepper. Maybe the programs are too simple
so far for the stepper, but it doesn't step.

The check syntax feature is great. for the check-color game should the
stepper work? What is the trick? I just wanted to check the flow by stepping
through.
Each time I use it I get "Couldn't find a step matching that criterion"
No matter what I change select or do.

;check-color
;colour guessing game (target target)(guess guess)
;symbol symbol symbol symbol -> string
;four color symbols
(define (check-color target1 target2 guess1 guess2)
  (cond
    [(eq? target1 guess1) 'Perfect]
    [(or (eq? target1 guess1)(eq? target2 guess2))
'OneColorAtCorrectPosition]
    [(or (eq? target1 guess2)(eq? target2 guess1)) 'OneColorOccurs]
    [else 'NothingCorrect]))

;(check-color 'red 'green 'green 'red)
;'OneColorOccurs

Sayth
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