--- a/UILayoutTool.st	Sun Dec 21 17:02:44 2014 +0100
+++ b/UILayoutTool.st	Tue Jan 27 13:16:28 2015 +0100
@@ -11,6 +11,8 @@
 "
 "{ Package: 'stx:libtool2' }"
 
+"{ NameSpace: Smalltalk }"
+
 ApplicationModel subclass:#UILayoutTool
 	instanceVariableNames:'modifiedHolder aspects selection currentTool layoutView tabList
 		layoutSpec toolsDictionary'
@@ -1706,12 +1708,13 @@
 
     (self aspectFor:#leftOffset)  value:(extent x).
     (self aspectFor:#topOffset)   value:(extent y).
-
-    (self aspectFor:#usePreferredWidth) value:(aSpec usePreferredWidth).
-    (self aspectFor:#usePreferredHeight) value:(aSpec usePreferredHeight).
-    (self aspectFor:#useDynamicPreferredWidth) value:(aSpec useDynamicPreferredWidth).
-    (self aspectFor:#useDynamicPreferredHeight) value:(aSpec useDynamicPreferredHeight).
-    (self aspectFor:#useDefaultExtent) value:aSpec useDefaultExtent 
+    aSpec notNil ifTrue:[
+        (self aspectFor:#usePreferredWidth) value:(aSpec usePreferredWidth).
+        (self aspectFor:#usePreferredHeight) value:(aSpec usePreferredHeight).
+        (self aspectFor:#useDynamicPreferredWidth) value:(aSpec useDynamicPreferredWidth).
+        (self aspectFor:#useDynamicPreferredHeight) value:(aSpec useDynamicPreferredHeight).
+        (self aspectFor:#useDefaultExtent) value:aSpec useDefaultExtent 
+    ].
 !
 
 layout