--- a/windowing/windowserver/nga/SERVER/drawresource.cpp	Wed Mar 31 23:34:07 2010 +0300
+++ b/windowing/windowserver/nga/SERVER/drawresource.cpp	Wed Apr 14 17:19:46 2010 +0300
@@ -45,6 +45,7 @@
 		User::Leave(KErrArgument);
 		}
 	MWsScreen* pOI=screen;
+	WS_ASSERT_ALWAYS(pOI, EWsPanicNoScreen);
 	CWsDrawableSource::iDrawResource = pOI->ObjectInterface<MWsDrawableSourceProvider>();
 	if (!iDrawResource)
 		{