--- a/SimpleView.st	Thu Sep 08 06:46:34 2016 +0200
+++ b/SimpleView.st	Sat Sep 10 06:51:32 2016 +0200
@@ -7498,13 +7498,13 @@
 forceUngrabKeyboard
     "force a keyboard ungrab - even if was not the grabber"
 
-    device ungrabKeyboard.
+    device notNil ifTrue:[ gc device ungrabKeyboard ].
 !
 
 forceUngrabPointer
     "force a pointer ungrab - even if was not the grabber"
 
-    device ungrabPointer
+    device notNil ifTrue:[ device ungrabPointer ]
 !
 
 grabKeyboard