Index: gc_core/py/lang_core/gc_engine.py
==================================================================
--- gc_core/py/lang_core/gc_engine.py
+++ gc_core/py/lang_core/gc_engine.py
@@ -586,10 +586,11 @@
     def __init__ (self, sSentence, sSentence0, nOffset):
         self.sSentence = sSentence
         self.sSentence0 = sSentence0
         self.nOffset = nOffset
         self.lToken = list(_oTokenizer.genTokens(sSentence, True))
+        self.dTokenPos = { dToken["nStart"]: dToken  for dToken in self.lToken }
         self.createError = self._createWriterError  if _bWriterError  else self._createDictError
 
     def update (self, sSentence):
         self.sSentence = sSentence
         self.lToken = list(_oTokenizer.genTokens(sSentence, True))