diff --git a/src/Graphics/XDot/Viewer.hs b/src/Graphics/XDot/Viewer.hs
--- a/src/Graphics/XDot/Viewer.hs
+++ b/src/Graphics/XDot/Viewer.hs
@@ -128,13 +128,10 @@
 
 draw _ (_, Polyline []) = return []
 
-draw hover (mn, BSpline a@((x,y):xys) filled) = do
+draw hover (mn, BSpline ((x,y):xys) filled) = do
   stylizedDraw filled hover mn $ do
     moveTo x y
     drawBezier xys
-
-  let xs = x : map fst a
-  let ys = y : map snd a
 
   return $ case mn of
     None -> []
diff --git a/xdot.cabal b/xdot.cabal
--- a/xdot.cabal
+++ b/xdot.cabal
@@ -1,5 +1,5 @@
 name:               xdot
-version:            0.2.3
+version:            0.2.3.1
 license:            BSD3
 license-file:       LICENSE
 category:           Graphs, Graphics
@@ -33,7 +33,7 @@
                  gtk == 0.12.*,
                  graphviz == 2999.16.*,
                  text == 0.11.*,
-                 polyparse == 1.8.*
+                 polyparse >= 1.8 && < 1.10
   Hs-source-dirs: src/
   Ghc-options: -Wall -fno-warn-unused-do-bind