diff --git a/src/gtkutil.c b/src/gtkutil.c
index 6308c38f16..7a1dd15ade 100644
--- a/src/gtkutil.c
+++ b/src/gtkutil.c
@@ -953,6 +953,7 @@ xg_frame_set_char_size (struct frame *f, int width, int height)
   int totalheight
     = pixelheight + FRAME_TOOLBAR_HEIGHT (f) + FRAME_MENUBAR_HEIGHT (f);
   int totalwidth = pixelwidth + FRAME_TOOLBAR_WIDTH (f);
+  GdkWindow *window = gtk_widget_get_window (FRAME_GTK_OUTER_WIDGET (f));

   if (FRAME_PIXEL_HEIGHT (f) == 0)
     return;
@@ -983,8 +984,7 @@ xg_frame_set_char_size (struct frame *f, int width, int height)
 	(f, Qxg_frame_set_char_size_1, width, height,
 	 list2i (gheight, totalheight));

-      gtk_window_resize (GTK_WINDOW (FRAME_GTK_OUTER_WIDGET (f)),
-			 gwidth, totalheight);
+      gdk_window_resize (window, gwidth, totalheight);
     }
   else if (EQ (fullscreen, Qfullheight) && height == FRAME_TEXT_HEIGHT (f))
     {
@@ -992,8 +992,7 @@ xg_frame_set_char_size (struct frame *f, int width, int height)
 	(f, Qxg_frame_set_char_size_2, width, height,
 	 list2i (gwidth, totalwidth));

-      gtk_window_resize (GTK_WINDOW (FRAME_GTK_OUTER_WIDGET (f)),
-			 totalwidth, gheight);
+      gdk_window_resize (window, totalwidth, gheight);
     }
   else
     {
@@ -1001,8 +1000,7 @@ xg_frame_set_char_size (struct frame *f, int width, int height)
 	(f, Qxg_frame_set_char_size_3, width, height,
 	 list2i (totalwidth, totalheight));

-      gtk_window_resize (GTK_WINDOW (FRAME_GTK_OUTER_WIDGET (f)),
-			 totalwidth, totalheight);
+      gdk_window_resize (window, totalwidth, totalheight);
       fullscreen = Qnil;
     }