src/Pure/PIDE/markup_tree.scala

       if (body.elements match { case Some(es) => es.exists(entry.elements) case None => true }) {
         val (y, changed) =
           (entry.markup :\ (x, false))((info, res) =>
             {
               val (y, changed) = res
-              val arg = (x, Text.Info(entry.range, info))
+              val arg = (y, Text.Info(entry.range, info))
               if (body.result.isDefinedAt(arg)) (body.result(arg), true)
               else res
             })
         if (changed) Some(y) else None
       }