--- a/WindowSensor.st	Fri Oct 29 18:42:33 1999 +0200
+++ b/WindowSensor.st	Wed Nov 03 09:50:08 1999 +0100
@@ -382,7 +382,10 @@
     EventListeners isNil ifTrue:[
         EventListeners := OrderedCollection new:2
     ].
-    EventListeners add:aListener
+
+    (EventListeners identityIndexOf:aListener) == 0 ifTrue:[
+        EventListeners add:aListener
+    ]
 !
 
 composeTable
@@ -2919,6 +2922,6 @@
 !WindowSensor class methodsFor:'documentation'!
 
 version
-    ^ '$Header: /cvs/stx/stx/libview/WindowSensor.st,v 1.167 1999-10-28 14:49:46 cg Exp $'
+    ^ '$Header: /cvs/stx/stx/libview/WindowSensor.st,v 1.168 1999-11-03 08:50:08 ca Exp $'
 ! !
 WindowSensor initialize!