--- a/Tools__TextDiff2Tool.st	Wed Feb 25 17:11:15 2015 +0100
+++ b/Tools__TextDiff2Tool.st	Wed Feb 25 17:15:39 2015 +0100
@@ -465,12 +465,14 @@
         self updateViews.            
         ^ self.
     ].
-    diffView notNil ifTrue:[    
-        ((changedObject == diffView leftTextView modifiedChannel) 
-        or:[changedObject == diffView rightTextView modifiedChannel]) ifTrue:[
-            self enqueueMessage:#updateDiffFromChangedText for:self arguments:#().
-            ^ self.    
-        ]
+    diffView notNil ifTrue:[
+        (diffView respondsTo:#leftTextView) ifTrue:[
+            ((changedObject == diffView leftTextView modifiedChannel) 
+            or:[changedObject == diffView rightTextView modifiedChannel]) ifTrue:[
+                self enqueueMessage:#updateDiffFromChangedText for:self arguments:#().
+                ^ self.    
+            ]
+        ].
     ].
 
     super update:something with:aParameter from:changedObject
@@ -632,11 +634,11 @@
 !TextDiff2Tool class methodsFor:'documentation'!
 
 version
-    ^ '$Header: /cvs/stx/stx/libtool/Tools__TextDiff2Tool.st,v 1.4 2015-02-13 19:49:31 cg Exp $'
+    ^ '$Header: /cvs/stx/stx/libtool/Tools__TextDiff2Tool.st,v 1.5 2015-02-25 16:15:39 cg Exp $'
 !
 
 version_CVS
-    ^ '$Id: Tools__TextDiff2Tool.st,v 1.4 2015-02-13 19:49:31 cg Exp $'
+    ^ '$Id: Tools__TextDiff2Tool.st,v 1.5 2015-02-25 16:15:39 cg Exp $'
 !
 
 version_HG
@@ -645,6 +647,6 @@
 !
 
 version_SVN
-    ^ '$Id: Tools__TextDiff2Tool.st,v 1.4 2015-02-13 19:49:31 cg Exp $'
+    ^ '$Id: Tools__TextDiff2Tool.st,v 1.5 2015-02-25 16:15:39 cg Exp $'
 ! !