Helper/Order.php
public function setOrderUserNote($order, $userNote)
    {
        $order
            ->addStatusHistoryComment($userNote)
            ->setIsVisibleOnFront(true)
            ->setIsCustomerNotified(false);

        return $order;
    }
public function setOrderUserNote($order, $userNote)
    {
        $order
            ->addStatusHistoryComment($userNote)
            ->setIsVisibleOnFront(true)
            ->setIsCustomerNotified(false);

        return $order;
    }
public function setOrderUserNote ( $ order , $ userNote ) { $ order -> addStatusHistoryComment ( $ userNote ) -> setIsVisibleOnFront ( true ) -> setIsCustomerNotified ( false ) ; return $ order ; }
Add user note as status history comment

@param OrderModel $order
@param string     $userNote

@return OrderModel
Add user note as status history comment