diff --git a/gui-lib/mred/private/moredialogs.rkt b/gui-lib/mred/private/moredialogs.rkt
index 5a1a0ab0..8fb2dbdb 100644
--- a/gui-lib/mred/private/moredialogs.rkt
+++ b/gui-lib/mred/private/moredialogs.rkt
@@ -305,13 +305,16 @@
          [(eq? (wx:color-from-user-platform-mode) 'dialog)
           (wx:get-color-from-user message (and parent (mred->wx parent)) in-color)]
          [else
-          (define color (if (member 'alpha style)
-                            in-color
-                            (make-object wx:color%
-                              (send in-color red)
-                              (send in-color green)
-                              (send in-color blue)
-                              1.0)))
+          (define color (cond
+                         [in-color
+                          (if (member 'alpha style)
+                              in-color
+                              (make-object wx:color%
+                                           (send in-color red)
+                                           (send in-color green)
+                                           (send in-color blue)
+                                           1.0))]
+                         [else (make-object wx:color% 0 0 0)]))
           (define ok? #f)
           (define f (make-object dialog% "Choose Color" parent))
           (define (done ok) (lambda (b e) (set! ok? ok) (send f show #f)))
diff --git a/gui-lib/mred/private/wx/cocoa/colordialog.rkt b/gui-lib/mred/private/wx/cocoa/colordialog.rkt
index 6a44e0f0..ba5f13e5 100644
--- a/gui-lib/mred/private/wx/cocoa/colordialog.rkt
+++ b/gui-lib/mred/private/wx/cocoa/colordialog.rkt
@@ -16,8 +16,9 @@
 
 (define-cocoa NSDeviceRGBColorSpace _id)
 
-(define (get-color-from-user mode)
+(define (get-color-from-user message parent color)
   (promote-to-gui!)
+  (define mode 'get)
   (cond
    [(eq? mode 'show)
     (tellv (tell NSColorPanel sharedColorPanel)
diff --git a/gui-lib/mred/private/wx/cocoa/procs.rkt b/gui-lib/mred/private/wx/cocoa/procs.rkt
index d0744e74..24f97297 100644
--- a/gui-lib/mred/private/wx/cocoa/procs.rkt
+++ b/gui-lib/mred/private/wx/cocoa/procs.rkt
@@ -74,7 +74,7 @@
 (define (find-graphical-system-path what)
   #f)
 
-(define (color-from-user-platform-mode) "Show Picker")
+(define (color-from-user-platform-mode) #f) ; implementation in "colordialog.rkt" is incomplete
 
 (define-unimplemented get-font-from-user)
 (define (font-from-user-platform-mode) #f)