--- a/Tools__NewSystemBrowser.st	Sat Jun 06 06:39:51 2015 +0200
+++ b/Tools__NewSystemBrowser.st	Sun Jun 07 06:39:04 2015 +0200
@@ -32991,7 +32991,9 @@
         |oldProjectDefinition|
 
         oldProjectDefinition := (oldPackagePerClass at:class) asPackageId projectDefinitionClass.
-        oldProjectDefinition excludeClasses:{class} usingCompiler:nil.
+        oldProjectDefinition notNil ifTrue:[
+            oldProjectDefinition excludeClasses:{class} usingCompiler:nil.
+        ].
     ].
 
     newProjectDefinition includeClasses:(classesAlreadyInRepository , classesNotYetInRepository) usingCompiler:nil.   
@@ -62633,11 +62635,11 @@
 !NewSystemBrowser class methodsFor:'documentation'!
 
 version
-    ^ '$Header: /cvs/stx/stx/libtool/Tools__NewSystemBrowser.st,v 1.2227 2015-05-31 09:26:27 cg Exp $'
+    ^ '$Header: /cvs/stx/stx/libtool/Tools__NewSystemBrowser.st,v 1.2228 2015-06-06 07:59:29 cg Exp $'
 !
 
 version_CVS
-    ^ '$Header: /cvs/stx/stx/libtool/Tools__NewSystemBrowser.st,v 1.2227 2015-05-31 09:26:27 cg Exp $'
+    ^ '$Header: /cvs/stx/stx/libtool/Tools__NewSystemBrowser.st,v 1.2228 2015-06-06 07:59:29 cg Exp $'
 !
 
 version_HG
@@ -62646,7 +62648,7 @@
 !
 
 version_SVN
-    ^ '$Id: Tools__NewSystemBrowser.st,v 1.2227 2015-05-31 09:26:27 cg Exp $'
+    ^ '$Id: Tools__NewSystemBrowser.st,v 1.2228 2015-06-06 07:59:29 cg Exp $'
 ! !