diff --git a/mozilla/gfx/src/gtk/gtkdrawing.c b/mozilla/gfx/src/gtk/gtkdrawing.c
index cb4db7a98ff..84bfbd0517b 100644
--- a/mozilla/gfx/src/gtk/gtkdrawing.c
+++ b/mozilla/gfx/src/gtk/gtkdrawing.c
@@ -205,7 +205,7 @@ moz_gtk_checkbox_paint(GdkWindow* window, GtkStyle* style,
   TSOffsetStyleGCs(style, x, y);
 
   /* Some themes check the widget state themselves. */
-  gtk_toggle_button_set_active(gCheckboxWidget, selected);
+  gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(gCheckboxWidget), selected);
 
   if (isradio)
     gtk_paint_option(style, window, state_type, shadow_type, cliprect,