src/Tools/jEdit/src/isabelle.scala

   def update_dictionary(text_area: JEditTextArea, include: Boolean, permanent: Boolean)
   {
     for {
       spell_checker <- PIDE.spell_checker.get
       doc_view <- PIDE.document_view(text_area)
-      Text.Info(_, word) <- Spell_Checker.current_word(text_area, doc_view.get_rendering())
+      rendering = doc_view.get_rendering()
+      range = JEdit_Lib.before_caret_range(text_area, rendering)
+      Text.Info(_, word) <- Spell_Checker.current_word(text_area, rendering, range)
     } {
       spell_checker.update(word, include, permanent)
       JEdit_Lib.jedit_views().foreach(_.repaint())
     }
   }