diff --git a/collects/mred/private/const.rkt b/collects/mred/private/const.rkt
index bab6a76d..d341e730 100644
--- a/collects/mred/private/const.rkt
+++ b/collects/mred/private/const.rkt
@@ -38,7 +38,11 @@
   (define arrow-cursor (make-object wx:cursor% 'arrow))
 
   (define default-x-prefix (if (eq? 'unix (system-type))
-			       (let ([v (get-preference '|GRacket:defaultMenuPrefix| (lambda () 'ctl))])
+			       (let ([v (get-preference 
+                                         '|GRacket:defaultMenuPrefix| 
+                                         ;; on fail, fall back to old name of pref:
+                                         (lambda () (get-preference '|MrEd:defaultMenuPrefix| 
+                                                                    (lambda () 'ctl))))])
 				 (if (memq v '(meta ctl alt ctl-m))
 				     v
 				     'ctl))