--- a/UIPainterView.st	Wed Dec 20 12:27:17 2000 +0100
+++ b/UIPainterView.st	Thu Dec 21 14:07:39 2000 +0100
@@ -214,8 +214,9 @@
 !UIPainterView methodsFor:'change & update'!
 
 layoutChanged
-
-    treeView layoutChanged
+    treeView notNil ifTrue:[
+        treeView layoutChanged
+    ]
 ! !
 
 !UIPainterView methodsFor:'copy & cut & paste'!