diff --git a/src/Pure/Thy/thy_header.scala b/src/Pure/Thy/thy_header.scala
--- a/src/Pure/Thy/thy_header.scala
+++ b/src/Pure/Thy/thy_header.scala
@@ -1,268 +1,268 @@
 /*  Title:      Pure/Thy/thy_header.scala
     Author:     Makarius
 
 Static theory header information.
 */
 
 package isabelle
 
 
 import scala.util.parsing.input.Reader
 import scala.util.matching.Regex
 
 
 object Thy_Header
 {
   /* bootstrap keywords */
 
   type Keywords = List[(String, Keyword.Spec)]
   type Abbrevs = List[(String, String)]
 
   val CHAPTER = "chapter"
   val SECTION = "section"
   val SUBSECTION = "subsection"
   val SUBSUBSECTION = "subsubsection"
   val PARAGRAPH = "paragraph"
   val SUBPARAGRAPH = "subparagraph"
   val TEXT = "text"
   val TXT = "txt"
   val TEXT_RAW = "text_raw"
 
   val THEORY = "theory"
   val IMPORTS = "imports"
   val KEYWORDS = "keywords"
   val ABBREVS = "abbrevs"
   val AND = "and"
   val BEGIN = "begin"
 
   val bootstrap_header: Keywords =
     List(
       ("%", Keyword.Spec()),
       ("(", Keyword.Spec()),
       (")", Keyword.Spec()),
       (",", Keyword.Spec()),
       ("::", Keyword.Spec()),
       ("=", Keyword.Spec()),
       (AND, Keyword.Spec()),
       (BEGIN, Keyword.Spec(kind = Keyword.QUASI_COMMAND)),
       (IMPORTS, Keyword.Spec(kind = Keyword.QUASI_COMMAND)),
       (KEYWORDS, Keyword.Spec(kind = Keyword.QUASI_COMMAND)),
       (ABBREVS, Keyword.Spec(kind = Keyword.QUASI_COMMAND)),
       (CHAPTER, Keyword.Spec(kind = Keyword.DOCUMENT_HEADING)),
       (SECTION, Keyword.Spec(kind = Keyword.DOCUMENT_HEADING)),
       (SUBSECTION, Keyword.Spec(kind = Keyword.DOCUMENT_HEADING)),
       (SUBSUBSECTION, Keyword.Spec(kind = Keyword.DOCUMENT_HEADING)),
       (PARAGRAPH, Keyword.Spec(kind = Keyword.DOCUMENT_HEADING)),
       (SUBPARAGRAPH, Keyword.Spec(kind = Keyword.DOCUMENT_HEADING)),
       (TEXT, Keyword.Spec(kind = Keyword.DOCUMENT_BODY)),
       (TXT, Keyword.Spec(kind = Keyword.DOCUMENT_BODY)),
       (TEXT_RAW, Keyword.Spec(kind = Keyword.DOCUMENT_RAW)),
       (THEORY, Keyword.Spec(kind = Keyword.THY_BEGIN, tags = List("theory"))),
       ("ML", Keyword.Spec(kind = Keyword.THY_DECL, tags = List("ML"))))
 
   private val bootstrap_keywords =
     Keyword.Keywords.empty.add_keywords(bootstrap_header)
 
   val bootstrap_syntax: Outer_Syntax =
     Outer_Syntax.empty.add_keywords(bootstrap_header)
 
 
   /* file name vs. theory name */
 
   val PURE = "Pure"
   val ML_BOOTSTRAP = "ML_Bootstrap"
   val ml_roots = List("ROOT0.ML" -> "ML_Root0", "ROOT.ML" -> "ML_Root")
   val bootstrap_thys = List(PURE, ML_BOOTSTRAP).map(a => a -> ("Bootstrap_" + a))
 
   val bootstrap_global_theories =
     (Sessions.root_name :: (ml_roots ::: bootstrap_thys).map(_._2)).map(_ -> PURE)
 
   private val Thy_File_Name = new Regex(""".*?([^/\\:]+)\.thy""")
   private val Split_File_Name = new Regex("""(.*?)[/\\]*([^/\\:]+)""")
   private val File_Name = new Regex(""".*?([^/\\:]+)""")
 
   def is_base_name(s: String): Boolean =
     s != "" && !s.exists("/\\:".contains(_))
 
   def split_file_name(s: String): Option[(String, String)] =
     s match {
       case Split_File_Name(s1, s2) => Some((s1, s2))
       case _ => None
     }
 
   def import_name(s: String): String =
     s match {
       case File_Name(name) if !name.endsWith(".thy") => name
       case _ => error("Malformed theory import: " + quote(s))
     }
 
   def theory_name(s: String): String =
     s match {
       case Thy_File_Name(name) => bootstrap_name(name)
       case File_Name(name) =>
         if (name == Sessions.root_name) name
         else ml_roots.collectFirst({ case (a, b) if a == name => b }).getOrElse("")
       case _ => ""
     }
 
   def is_ml_root(theory: String): Boolean =
     ml_roots.exists({ case (_, b) => b == theory })
 
   def is_bootstrap(theory: String): Boolean =
     bootstrap_thys.exists({ case (_, b) => b == theory })
 
   def bootstrap_name(theory: String): String =
     bootstrap_thys.collectFirst({ case (a, b) if a == theory => b }).getOrElse(theory)
 
   def try_read_dir(dir: Path): List[String] =
   {
     val files =
       try { File.read_dir(dir) }
       catch { case ERROR(_) => Nil }
     for { Thy_File_Name(name) <- files } yield name
   }
 
 
   /* parser */
 
   trait Parser extends Parse.Parser
   {
     val header: Parser[Thy_Header] =
     {
       val load_command =
         ($$$("(") ~! (position(name) <~ $$$(")")) ^^ { case _ ~ x => x }) |
           success(("", Position.none))
 
       val keyword_kind = atom("outer syntax keyword specification", _.is_name)
       val keyword_spec =
         position(keyword_kind) ~ load_command ~ tags ^^
           { case (a, b) ~ c ~ d =>
               Keyword.Spec(kind = a, kind_pos = b,
                 load_command = c._1, load_command_pos = c._2, tags = d)
           }
 
       val keyword_decl =
         rep1(string) ~
         opt($$$("::") ~! keyword_spec ^^ { case _ ~ x => x }) ^^
         { case xs ~ y => xs.map((_, y.getOrElse(Keyword.Spec()))) }
 
       val keyword_decls =
         keyword_decl ~ rep($$$(AND) ~! keyword_decl ^^ { case _ ~ x => x }) ^^
         { case xs ~ yss => (xs :: yss).flatten }
 
       val abbrevs =
         rep1sep(rep1(text) ~ ($$$("=") ~! rep1(text)), $$$("and")) ^^
           { case res => for ((as ~ (_ ~ bs)) <- res; a <- as; b <- bs) yield (a, b) }
 
       val args =
         position(theory_name) ~
         (opt($$$(IMPORTS) ~! rep1(position(theory_name))) ^^
           { case None => Nil case Some(_ ~ xs) => xs }) ~
         (opt($$$(KEYWORDS) ~! keyword_decls) ^^
           { case None => Nil case Some(_ ~ xs) => xs }) ~
         (opt($$$(ABBREVS) ~! abbrevs) ^^
           { case None => Nil case Some(_ ~ xs) => xs }) ~
-        $$$(BEGIN) ^^ { case a ~ b ~ c ~ d ~ _ => Thy_Header(a._1, a._2, b, c, d).map(Symbol.decode) }
+        $$$(BEGIN) ^^ { case a ~ b ~ c ~ d ~ _ => Thy_Header(a._1, a._2, b, c, d) }
 
       val heading =
         (command(CHAPTER) |
           command(SECTION) |
           command(SUBSECTION) |
           command(SUBSUBSECTION) |
           command(PARAGRAPH) |
           command(SUBPARAGRAPH) |
           command(TEXT) |
           command(TXT) |
           command(TEXT_RAW)) ~
         annotation ~! document_source
 
       (rep(heading) ~ command(THEORY) ~ annotation) ~! args ^^ { case _ ~ x => x }
     }
   }
 
 
   /* read -- lazy scanning */
 
   private def read_tokens(reader: Reader[Char], strict: Boolean): (List[Token], List[Token]) =
   {
     val token = Token.Parsers.token(bootstrap_keywords)
     def make_tokens(in: Reader[Char]): Stream[Token] =
       token(in) match {
         case Token.Parsers.Success(tok, rest) => tok #:: make_tokens(rest)
         case _ => Stream.empty
       }
 
     val all_tokens = make_tokens(reader)
     val drop_tokens =
       if (strict) Nil
       else all_tokens.takeWhile(tok => !tok.is_command(Thy_Header.THEORY)).toList
 
     val tokens = all_tokens.drop(drop_tokens.length)
     val tokens1 = tokens.takeWhile(tok => !tok.is_begin).toList
     val tokens2 = tokens.dropWhile(tok => !tok.is_begin).headOption.toList
 
     (drop_tokens, tokens1 ::: tokens2)
   }
 
   private object Parser extends Parser
   {
     def parse_header(tokens: List[Token], pos: Token.Pos): Thy_Header =
       parse(commit(header), Token.reader(tokens, pos)) match {
         case Success(result, _) => result
         case bad => error(bad.toString)
       }
   }
 
   def read(node_name: Document.Node.Name, reader: Reader[Char],
     command: Boolean = true,
     strict: Boolean = true): Thy_Header =
   {
     val (_, tokens0) = read_tokens(reader, true)
     val text = Scan.reader_decode_utf8(reader, Token.implode(tokens0))
 
     val (skip_tokens, tokens) = read_tokens(Scan.char_reader(text), strict)
     val pos =
       if (command) Token.Pos.command
       else (Token.Pos.file(node_name.node) /: skip_tokens)(_ advance _)
 
-    Parser.parse_header(tokens, pos).check(node_name)
+    Parser.parse_header(tokens, pos).map(Symbol.decode).check(node_name)
   }
 }
 
 sealed case class Thy_Header(
   name: String,
   pos: Position.T,
   imports: List[(String, Position.T)],
   keywords: Thy_Header.Keywords,
   abbrevs: Thy_Header.Abbrevs)
 {
   def map(f: String => String): Thy_Header =
     Thy_Header(f(name), pos,
       imports.map({ case (a, b) => (f(a), b) }),
       keywords.map({ case (a, spec) => (f(a), spec.map(f)) }),
       abbrevs.map({ case (a, b) => (f(a), f(b)) }))
 
   def check(node_name: Document.Node.Name): Thy_Header =
   {
     val base_name = node_name.theory_base_name
     if (Long_Name.is_qualified(name)) {
       error("Bad theory name " + quote(name) + " with qualification" + Position.here(pos))
     }
     if (base_name != name) {
       error("Bad theory name " + quote(name) + " for file " + Path.basic(base_name).thy +
         Position.here(pos) + Completion.report_theories(pos, List(base_name)))
     }
 
     for ((_, spec) <- keywords) {
       if (spec.kind != Keyword.THY_LOAD && spec.load_command.nonEmpty) {
         error("Illegal load command specification for kind: " + quote(spec.kind) +
           Position.here(spec.kind_pos))
       }
       if (!Command_Span.load_commands.exists(_.name == spec.load_command)) {
         error("Unknown load command specification: " + quote(spec.load_command) +
           Position.here(spec.load_command_pos))
       }
     }
     this
   }
 }