diff -r 3ba988e35485 -r 4454dc8e0b06 ApplicationModel.st --- a/ApplicationModel.st Wed Nov 18 13:10:31 2015 +0100 +++ b/ApplicationModel.st Sat Nov 21 00:21:14 2015 +0100 @@ -1,5 +1,3 @@ -"{ Encoding: utf8 }" - " COPYRIGHT (c) 1995 by Claus Gittinger All Rights Reserved @@ -2754,7 +2752,10 @@ initializeScreenDevice Screen notNil ifTrue:[ - device := Screen current. + device := Screen current. + device isOpen ifFalse:[ + self error:'screen device is not open' + ]. ] !