--- a/MemoryUsageView.st	Tue Feb 20 17:39:48 2001 +0100
+++ b/MemoryUsageView.st	Tue Feb 20 18:07:26 2001 +0100
@@ -580,7 +580,7 @@
 
 "/              o isBehavior ifTrue:[
                 class := o class.
-                (class flags bitAnd:behaviorFlag) ~~ 0 ifTrue:[
+                (class flags notNil and:[(class flags bitAnd:behaviorFlag) ~~ 0]) ifTrue:[
                     o isObsolete ifTrue:[
                         class := #ObsoleteClass
                     ] ifFalse:[
@@ -645,5 +645,5 @@
 !MemoryUsageView class methodsFor:'documentation'!
 
 version
-    ^ '$Header: /cvs/stx/stx/libtool/MemoryUsageView.st,v 1.42 2000-11-20 17:59:27 cg Exp $'
+    ^ '$Header: /cvs/stx/stx/libtool/MemoryUsageView.st,v 1.43 2001-02-20 17:07:26 cg Exp $'
 ! !