diff --git a/graphmod.cabal b/graphmod.cabal
--- a/graphmod.cabal
+++ b/graphmod.cabal
@@ -1,5 +1,5 @@
 name:           graphmod
-version:        1.2
+version:        1.2.1
 license:        BSD3
 license-file:   LICENSE
 author:         Iavor S. Diatchki
diff --git a/src/Main.hs b/src/Main.hs
--- a/src/Main.hs
+++ b/src/Main.hs
@@ -123,7 +123,7 @@
 
 collapse (Trie.Sub ts mb) [q] =
   do n <- getFirst =<< Map.lookup q ts
-     return $ Trie.Sub Map.empty $ Just
+     return $ Trie.Sub (Map.delete q ts) $ Just
                                  $ ((CollapsedNode,q),n) : fromMaybe [] mb
   where getFirst (Trie.Sub ts1 ms) =
           msum (fmap snd (listToMaybe =<< ms) : map getFirst (Map.elems ts1))