--- a/Tools__CodeHighlightingService.st	Thu Oct 16 13:05:41 2014 +0200
+++ b/Tools__CodeHighlightingService.st	Thu Oct 16 16:26:14 2014 +0200
@@ -294,11 +294,18 @@
 
     |firstShown lastShown cursorWasOn anyChange newLines l replaceAction list|
 
-    "textView" modified ifTrue:[
-        "/ new input arrived in the meantime
+    "/ It may happen that service is unregistered while
+    "/ an user event for #setHighlightedCode:elements: is already in
+    "/ an event queue but not yet processed. To handle this situation.
+    "/ check if textView is nil (which is in case the service is unregistered)
+    textView isNil ifTrue:[ ^ self ].
 
-        ^ self
+
+    modified ifTrue:[ 
+        "/ a new input arrived in the meantime
+        ^ self 
     ].
+
     done ifFalse:[
         "/ another coloring process has already been started.
         "/ ignore this (leftover) code.
@@ -378,20 +385,20 @@
     "Created: / 14-02-2010 / 16:10:21 / Jan Vrany <jan.vrany@fit.cvut.cz>"
     "Modified (format): / 21-08-2011 / 09:38:22 / cg"
     "Modified: / 01-02-2012 / 19:18:00 / jv"
-    "Modified: / 17-03-2012 / 19:33:18 / Jan Vrany <jan.vrany@fit.cvut.cz>"
+    "Modified: / 16-10-2014 / 12:28:54 / Jan Vrany <jan.vrany@fit.cvut.cz>"
 ! !
 
 !CodeHighlightingService class methodsFor:'documentation'!
 
 version
-    ^ '$Header: /cvs/stx/stx/libtool/Tools__CodeHighlightingService.st,v 1.49 2014-06-10 17:00:16 vrany Exp $'
+    ^ '$Header: /cvs/stx/stx/libtool/Tools__CodeHighlightingService.st,v 1.50 2014-10-16 14:26:14 vrany Exp $'
 !
 
 version_CVS
-    ^ '$Header: /cvs/stx/stx/libtool/Tools__CodeHighlightingService.st,v 1.49 2014-06-10 17:00:16 vrany Exp $'
+    ^ '$Header: /cvs/stx/stx/libtool/Tools__CodeHighlightingService.st,v 1.50 2014-10-16 14:26:14 vrany Exp $'
 !
 
 version_SVN
-    ^ '$Id: Tools__CodeHighlightingService.st,v 1.49 2014-06-10 17:00:16 vrany Exp $'
+    ^ '$Id: Tools__CodeHighlightingService.st,v 1.50 2014-10-16 14:26:14 vrany Exp $'
 ! !