WooCommerce: Coupon field doesn't show error or success messages after moving the form

Question

I've moved the coupon field in the cart from the items table to the cart totals table. Everything works fine so far. But after adding a code, the form doesn't show any error or success messages.

I tired to figure out why that's the case but couldn't find anything? Is there some javascript involved? Do I miss some classes?

Here's my current code:

<?php 
add_action( 'woocommerce_cart_totals_before_shipping', 'display_coupon_form_below_proceed_checkout', 100 );
function display_coupon_form_below_proceed_checkout() { ?>

   <?php if ( wc_coupons_enabled() ) { ?>
   <tr class="cart-discount-add">
        <th colspan="2">
            <a data-toggle="collapse" href="#collapseCartCoupon" role="button" aria-expanded="false" aria-controls="collapseCartCoupon">Add coupon code</a>
        </th>
    </tr>
    <tr class="cart-discount-form">
        <td colspan="2">
            <form class="woocommerce-coupon-form" action="<?php echo esc_url( wc_get_cart_url() ); ?>" method="post">
                <div class="coupon collapse" id="collapseCartCoupon">
                <div class="input-group">
                    <input type="text" name="coupon_code" class="form-control input-text" id="coupon_code" value="" placeholder="<?php esc_attr_e( 'Coupon code', 'woocommerce' ); ?>" />
                    <div class="input-group-append">
                        <button type="submit" class="button" name="apply_coupon" value="<?php esc_attr_e( 'Apply coupon', 'woocommerce' ); ?>"><?php esc_attr_e( 'Apply coupon', 'woocommerce' ); ?></button>
                    </div>
                </div>

                </div>
            </form>
        </td>
    </tr>
    <?php } ?>

<?php } ?>