--- a/SequenceView.st	Wed Feb 05 13:55:04 2020 +0100
+++ b/SequenceView.st	Thu Feb 06 12:13:41 2020 +0100
@@ -1,3 +1,5 @@
+"{ Encoding: utf8 }"
+
 "
  COPYRIGHT (c) 1997 by eXept Software AG
               All Rights Reserved
@@ -96,7 +98,7 @@
 enabled:aBoolean
     "senders assume that I am the listView - not a wrapper"
 
-    scrolledView enabled:aBoolean
+    scrolledView notNil ifTrue:[ scrolledView enabled:aBoolean ]
 !
 
 font:aFont
@@ -111,31 +113,31 @@
 invalidate
     "senders assume that I am the listView - not a wrapper"
 
-    scrolledView invalidate
+    scrolledView notNil ifTrue:[ scrolledView invalidate ]
 !
 
 invalidate:aRectangle
     "senders assume that I am the listView - not a wrapper"
 
-    scrolledView invalidate:aRectangle
+    scrolledView notNil ifTrue:[ scrolledView invalidate:aRectangle ]
 !
 
 invalidate:aRectangle repairNow:doRepair
     "senders assume that I am the listView - not a wrapper"
 
-    scrolledView invalidate:aRectangle repairNow:doRepair
+    scrolledView notNil ifTrue:[ scrolledView invalidate:aRectangle repairNow:doRepair ]
 !
 
 invalidateDeviceRectangle:aRectangle repairNow:doRepair
     "senders assume that I am the listView - not a wrapper"
 
-    scrolledView invalidateDeviceRectangle:aRectangle repairNow:doRepair
+    scrolledView notNil ifTrue:[ scrolledView invalidateDeviceRectangle:aRectangle repairNow:doRepair ]
 !
 
 invalidateRepairNow:doRepair
     "senders assume that I am the listView - not a wrapper"
 
-    scrolledView invalidateRepairNow:doRepair
+    scrolledView notNil ifTrue:[ scrolledView invalidateRepairNow:doRepair ]
 ! !
 
 !SequenceView class methodsFor:'documentation'!