diff --git a/Graphics/Diagram/Gtk.hs b/Graphics/Diagram/Gtk.hs
index 9b310d0..1464f85 100644
--- a/Graphics/Diagram/Gtk.hs
+++ b/Graphics/Diagram/Gtk.hs
@@ -38,7 +38,7 @@ diag p pts = case alg p of
   where
     polys =
       mkDiag
-        (mconcat [maybeDiag (ct p) coordPointsText, polyLines])
+        (mconcat [maybeDiag (ct p) coordPointsText, coordPoints, polyLines])
         p (head pts)
       `atop`
       mkDiag