ISSUE: Checkout problem with promo codes

[jstrope]

In Prestashop 1.7, the only payment method we are using is the CashOnDelivery module.  When checking out, it correctly appears as an option to select. However, if you enter a promo code that brings the total cost down to 0(Free), there is no option to elect a payment method and it displays text that says "No payment needed for this order".  But because no payment method is selected, the Place order button is not active.  How do i either force the CashOnDelivery payment method to be auto-selected by default, or allow the Place order button to be enabled when a promo code has discounted the total to Free?