src/Pure/PIDE/markup_tree.scala

   private def this(branches: Markup_Tree.Branches.T, entry: Markup_Tree.Entry) =
     this(branches + (entry.range -> entry))
 
   private def overlapping(range: Text.Range): Branches.T =
     if (branches.isEmpty ||
-        (range.contains(branches.firstKey.start) && range.contains(branches.lastKey.stop)))
+        (range.contains(branches.firstKey.start) && branches.lastKey.stop <= range.stop))
       branches
     else {
       val start = Text.Range(range.start)
       val stop = Text.Range(range.stop)
       val bs = branches.range(start, stop)