diff --git a/docs/reference/gtk/Makefile.am b/docs/reference/gtk/Makefile.am
index 42d23fc1c1..94231fed3e 100644
--- a/docs/reference/gtk/Makefile.am
+++ b/docs/reference/gtk/Makefile.am
@@ -328,7 +328,7 @@ HTML_IMAGES = \
 	$(srcdir)/images/layout-tbrl.png				\
 	$(srcdir)/images/window-default.png				\
 	$(srcdir)/images/hello-world.png				\
-	$(srcdir)/images/switch.png
+	$(srcdir)/images/switch.png					\
 	$(srcdir)/images/linear.png					\
 	$(srcdir)/images/ease.png					\
 	$(srcdir)/images/ease-in-out.png				\