diff --git a/widget/src/Makefile.in b/widget/src/Makefile.in
index 7905487ab38..9e226ffa3c5 100644
--- a/widget/src/Makefile.in
+++ b/widget/src/Makefile.in
@@ -38,6 +38,7 @@ DIRS		= xpwidgets support
 ifndef MOZ_MONOLITHIC_TOOLKIT
 
 ifdef MOZ_ENABLE_GTK
+DIRS		+= gtksuperwin
 DIRS		+= gtk
 endif