src/Pure/Thy/thy_syntax.scala

--- a/src/Pure/Thy/thy_syntax.scala	Mon Nov 18 09:45:50 2013 +0100
+++ b/src/Pure/Thy/thy_syntax.scala	Mon Nov 18 17:16:56 2013 +0100
@@ -355,6 +355,8 @@
         else
           node.update_perspective(perspective).update_commands(
             consolidate_spans(syntax, reparse_limit, name, visible, node.commands))
+
+      case (_, Document.Node.Blob(blob)) => node.update_blob(blob)
     }
   }