diff --git a/pkgs/gui-pkgs/gui-lib/mred/private/wx/win32/button.rkt b/pkgs/gui-pkgs/gui-lib/mred/private/wx/win32/button.rkt
index 64334054..dc753eee 100644
--- a/pkgs/gui-pkgs/gui-lib/mred/private/wx/win32/button.rkt
+++ b/pkgs/gui-pkgs/gui-lib/mred/private/wx/win32/button.rkt
@@ -154,6 +154,13 @@
 				  xp-label-font))))
 	  (super set-label s)))
 
+    ;; Avoid passing any key event to a button or checkbox. The
+    ;; `pre-on-char` of the frame will take care of changing space to
+    ;; a control action, but the control itself may use WM_KEYDOWN
+    ;; instead of WM_CHAR.
+    (define/override (capture-all-key-events?)
+      #t)
+
     (define/override (is-command? cmd)
       (= cmd BN_CLICKED))
 
diff --git a/pkgs/gui-pkgs/gui-lib/mred/private/wx/win32/window.rkt b/pkgs/gui-pkgs/gui-lib/mred/private/wx/win32/window.rkt
index 2d007957..5326afe5 100644
--- a/pkgs/gui-pkgs/gui-lib/mred/private/wx/win32/window.rkt
+++ b/pkgs/gui-pkgs/gui-lib/mred/private/wx/win32/window.rkt
@@ -549,14 +549,15 @@
   
   (define/private (do-key w msg wParam lParam is-char? is-up? default)
     (let ([e (maybe-make-key-event #f wParam lParam is-char? is-up? hwnd)])
-      (if (and e
-               (if (definitely-wants-event? w msg wParam e)
-                   (begin
-                     (queue-window-event this (lambda () (dispatch-on-char/sync e)))
-                     #t)
-                   (constrained-reply eventspace
-                                      (lambda () (dispatch-on-char e #t))
-                                      #t)))
+      (if (or (and e
+		   (if (definitely-wants-event? w msg wParam e)
+		       (begin
+			 (queue-window-event this (lambda () (dispatch-on-char/sync e)))
+			 #t)
+		       (constrained-reply eventspace
+					  (lambda () (dispatch-on-char e #t))
+					  #t)))
+	      (capture-all-key-events?))
           0
           (default w msg wParam lParam))))
 
@@ -740,6 +741,8 @@
 
   (define/public (definitely-wants-event? w msg wParam e)
     #f)
+  (define/public (capture-all-key-events?)
+    #f)
 
   (define/public (dispatch-on-char/sync e)
     (pre-event-refresh #t)