[plt-scheme] MrEd - grid alignment

Hi,

how do I align several items in a grid (table) layout?

code example:

(define frame (instantiate frame% ("Haushaltsbuch")))

(define check-input (instantiate vertical-pane% (frame) (alignment '(left center))))

(map (lambda (x)
       (let ((parent (instantiate horizontal-pane% (check-input) (alignment '(center center)))))
         (list
          (instantiate message% (x parent))
          (instantiate text-field% (#f parent void) (min-width 100) (stretchable-width #f)))))
     '("Betrag" "Empfänger" "Verwendungszweck"))

(send frame show #t)

This unfortunately won't align to agrid though.

Guenther