--- a/UIPainter.st	Thu Feb 17 16:00:12 2000 +0100
+++ b/UIPainter.st	Thu Feb 17 16:00:43 2000 +0100
@@ -3687,7 +3687,9 @@
             list := cls perform:#aspectSelectors ifNotUnderstood:nil.
         ].
         spec setExportedAspectsFrom:list.
-        windowSpec exportedAspects:(spec exportedAspects).
+        windowSpec notNil ifTrue:[
+            windowSpec exportedAspects:(spec exportedAspects).
+        ]
     ].
 
     self propertiesDo:[:aProp| |aspect entry|