diff --git a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/rewrite/changegenerator/ChangeGenerator.java b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/rewrite/changegenerator/ChangeGenerator.java
index 1f3da625f7c..130901f1a75 100644
--- a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/rewrite/changegenerator/ChangeGenerator.java
+++ b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/rewrite/changegenerator/ChangeGenerator.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2008 Institute for Software, HSR Hochschule fuer Technik  
+ * Copyright (c) 2008, 2009 Institute for Software, HSR Hochschule fuer Technik  
  * Rapperswil, University of applied sciences and others
  * All rights reserved. This program and the accompanying materials 
  * are made available under the terms of the Eclipse Public License v1.0 
@@ -564,6 +564,7 @@ public class ChangeGenerator extends CPPASTVisitor {
 			do {
 				if (lastCommonPosition >= 0
 						&& lastCommonPositionInOriginal >= 0
+						&& lastCommonPositionInOriginal	- korOffset >= 0
 						&& originalCode.charAt(lastCommonPositionInOriginal
 								- korOffset) == reverseSynthCode
 								.charAt(lastCommonPosition)) {