--- a/ResourceSelectionBrowser.st	Thu Jun 18 17:07:13 1998 +0200
+++ b/ResourceSelectionBrowser.st	Thu Jun 18 19:15:53 1998 +0200
@@ -705,14 +705,14 @@
         ifTrue:
         [                            
             |superClasses nonSuperclasses item cls|
-            (cls := Smalltalk at: classSelection) isPrivate
+            ((cls := Smalltalk at: classSelection) notNil and: [cls isPrivate])
                 ifFalse: [superClasses := foundClass withAllSuperclasses reverse]
                 ifTrue:  [superClasses := cls owningClass withAllSuperclasses reverse. superClasses add: cls]
-.
+.                                  
             (nonSuperclasses := self treeViewContents allSuperclasses) notNil 
                 ifTrue: [superClasses := superClasses reject: [:cls| nonSuperclasses includes: cls]].
             item := self rootOfClasses detectChild:[:child :arg| child contents == arg] arguments:superClasses.
-            item notNil ifTrue:[self selectionOfClass value:item]
+            item notNil ifTrue:[self selectionOfClass value:item]  
         ].
         self valueOfClassName value: clsPattern
     ].