proper Symbol.decode -- especially relevant for Proof General;

--- a/src/Tools/Graphview/src/frame.scala	Wed Sep 26 14:55:51 2012 +0200
+++ b/src/Tools/Graphview/src/frame.scala	Wed Sep 26 14:56:59 2012 +0200
@@ -27,7 +27,7 @@
 
         args.toList match {
           case List(arg) =>
-            Model.decode_graph(YXML.parse_body(File.read(Path.explode(arg))))
+            Model.decode_graph(YXML.parse_body(Symbol.decode(File.read(Path.explode(arg)))))
           case _ => error("Bad arguments:\n" + cat_lines(args))
         }
       }