public void notifyGlasspaneListeners(boolean isShown) {
   if (isShown) {
     GlassPane.getInstance().show();
   } else {
     GlassPane.getInstance().hide();
   }
 }
 private void addGlassPaneListener(JavaScriptObject obj) {
   GlassPane.getInstance().addGlassPaneListener(new GlassPaneNativeListener(obj));
 }