code: public HandlerRegistration addChangedHandler(final ChangedHandler handler) {
  		return enabledForm.addItemChangedHandler(new ItemChangedHandler() {
  
  			public void onItemChanged(ItemChangedEvent event) {
  				handler.onChanged(new ChangedEvent(EnableToggleFormItem.this.getJsObj()));
  			}
  		});
  
  	}
docs: ------------------------------------------------------------------------