[racket] Undefined method get-hard-minimum-size

The following example raises this error:

send: no such method: get-hard-minimum-size for class: ...ed/private/wxtop.rkt:586:4

I'm trying in  DrRacket 5.02, under Windows XP
Regards
Maurizio.


#lang racket/gui
(define frame (new frame% [label "Example"]))

(define txt (new text-field% [parent frame] [label "This is s test"]))

(send frame show #t)
(define-values (x y) (send frame get-graphical-min-size))

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