--- a/ExternalStreamMonitor.st	Thu Feb 14 15:48:37 2019 +0100
+++ b/ExternalStreamMonitor.st	Thu Feb 14 15:48:59 2019 +0100
@@ -1,5 +1,3 @@
-"{ Encoding: utf8 }"
-
 "
  COPYRIGHT (c) 1997 by Claus Gittinger
 	      All Rights Reserved
@@ -306,7 +304,10 @@
         oldList := listView list.
         oldSelection := listView selection.
         oldSelection notNil ifTrue:[
-            oldSelection := oldSelection collect:[:lineNr | streams at:(lineNr - self numberOfHeadlines) ].
+            oldSelection := oldSelection 
+                                collect:[:lineNr | 
+                                    streams at:(lineNr - self numberOfHeadlines) ifAbsent:nil 
+                                ].
             newSelection := OrderedCollection new.
         ].
 
@@ -462,7 +463,7 @@
     self installDelayedUpdate.
 
     "Modified: / 11-10-2017 / 13:56:14 / cg"
-    "Modified: / 29-10-2018 / 15:33:31 / Claus Gittinger"
+    "Modified: / 14-02-2019 / 15:44:09 / Claus Gittinger"
 ! !
 
 !ExternalStreamMonitor methodsFor:'menu'!