1 files changed, 17 insertions, 2 deletions
diff --git a/csharp/ProtocolBuffers/Descriptors/MessageDescriptor.cs b/csharp/ProtocolBuffers/Descriptors/MessageDescriptor.cs
index 02343937..e3df02fe 100644
--- a/csharp/ProtocolBuffers/Descriptors/MessageDescriptor.cs
+++ b/csharp/ProtocolBuffers/Descriptors/MessageDescriptor.cs
@@ -1,4 +1,19 @@
-using System.Collections.Generic;
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.
+// http://code.google.com/p/protobuf/
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+using System.Collections.Generic;
 using Google.ProtocolBuffers.DescriptorProtos;
 
 namespace Google.ProtocolBuffers.Descriptors {
@@ -6,7 +21,7 @@ namespace Google.ProtocolBuffers.Descriptors {
   /// <summary>
   /// Describes a message type.
   /// </summary>
-  public class MessageDescriptor : IndexedDescriptorBase<DescriptorProto, MessageOptions> {
+  public sealed class MessageDescriptor : IndexedDescriptorBase<DescriptorProto, MessageOptions> {
 
     private readonly MessageDescriptor containingType;
     private readonly IList<MessageDescriptor> nestedTypes;