diff --git a/collects/mred/private/wx/gtk/dialog.rkt b/collects/mred/private/wx/gtk/dialog.rkt
index 56ba1e50..25be184c 100644
--- a/collects/mred/private/wx/gtk/dialog.rkt
+++ b/collects/mred/private/wx/gtk/dialog.rkt
@@ -12,8 +12,11 @@
 (define GTK_WIN_POS_CENTER 1)
 (define GTK_WIN_POS_CENTER_ON_PARENT 4)
 
+(define GDK_WINDOW_TYPE_HINT_DIALOG 1)
+
 (define-gtk gtk_window_set_position (_fun _GtkWidget _int -> _void))
 (define-gtk gtk_window_set_transient_for (_fun _GtkWidget _GtkWidget -> _void))
+(define-gtk gtk_window_set_type_hint (_fun _GtkWidget _int -> _void))
 
 (defclass dialog% frame%
   (inherit get-gtk
@@ -23,6 +26,8 @@
 
   (define close-sema #f)
 
+  (gtk_window_set_type_hint (get-gtk) GDK_WINDOW_TYPE_HINT_DIALOG)
+
   (let ([p (get-parent)])
     (when p
       (gtk_window_set_transient_for (get-gtk) (send p get-gtk))))