8256201: java/awt/FullScreen/FullscreenWindowProps/FullscreenWindowProps.java failed

Reviewed-by: jdv
diff --git a/test/jdk/java/awt/FullScreen/FullscreenWindowProps/FullscreenWindowProps.java b/test/jdk/java/awt/FullScreen/FullscreenWindowProps/FullscreenWindowProps.java
index d444ee5..1160c54 100644
--- a/test/jdk/java/awt/FullScreen/FullscreenWindowProps/FullscreenWindowProps.java
+++ b/test/jdk/java/awt/FullScreen/FullscreenWindowProps/FullscreenWindowProps.java
@@ -55,6 +55,7 @@
             }
         };
         try {
+            frame.setUndecorated(true); // workaround JDK-8256257
             frame.setBackground(Color.MAGENTA);
             frame.setVisible(true);
             gd.setFullScreenWindow(frame);
@@ -99,4 +100,4 @@
             throw new RuntimeException(prop + " is wrong");
         }
     }
-}
\ No newline at end of file
+}