--- a/UserPreferences.st	Wed Nov 02 15:21:53 2016 +0100
+++ b/UserPreferences.st	Wed Nov 02 16:22:32 2016 +0100
@@ -1,5 +1,3 @@
-"{ Encoding: utf8 }"
-
 "
  COPYRIGHT (c) 1998 by eXept Software AG
 	      All Rights Reserved
@@ -874,6 +872,8 @@
     ^ modified ? false
 ! !
 
+
+
 !UserPreferences methodsFor:'accessing-locale'!
 
 dateInputFormat
@@ -1861,8 +1861,9 @@
 enableVMWareDrawingBugWorkaround:aBoolean
     "change the flag which enables a workaround for a redraw bug when running X/Linux in the VMWare virtual machine"
 
+    "/ self assert:(aBoolean isBoolean).
     self at:#enableVMWareDrawingBugWorkaround put:aBoolean.
-    (Screen notNil and:[Screen current notNil and:[Screen current platformName == #X11]]) ifTrue:[
+    (Screen notNil and:[Screen current notNil and:[Screen current isX11Platform]]) ifTrue:[
         Screen current maxOperationsUntilFlush:(aBoolean ifTrue:[1] ifFalse:[nil])
     ].