--- a/GraphicsMedium.st	Tue Mar 20 12:02:05 2018 +0100
+++ b/GraphicsMedium.st	Tue Mar 20 12:52:39 2018 +0100
@@ -1,5 +1,3 @@
-"{ Encoding: utf8 }"
-
 "
  COPYRIGHT (c) 1989 by Claus Gittinger
 	      All Rights Reserved
@@ -69,11 +67,15 @@
     device := Screen current.
     device isNil ifTrue:[
         "/ there seems to be no current screen; open one.
-        Smalltalk openDisplay.
-        device := Screen current.
+        device := Smalltalk lateOpenDisplay.
+        device isNil ifTrue:[ 
+            Screen deviceOpenErrorSignal raiseErrorString:'no screen device'. 
+        ]
     ].
     
     ^ self onDevice:device.
+
+    "Modified: / 20-03-2018 / 12:49:17 / stefan"
 !
 
 on:aDevice