Force a menu on the checkout

-- HikaShop version -- : 2.4.0
-- Joomla version -- : 3.4.1
-- PHP version -- : 5.4.32
-- Browser(s) name and version -- : All
-- Error-message(debug-mod must be tuned on) -- : N/A

The "Force a menu on the checkout" option doesn't always work if the user is logged in and presses the "Proceed to checkout" multiple times.

To recreate this error you can log in as username test4 with the password test4. Then add any product(s) to the cart and click the proceed to cart button multiple times. Most of the time it will redirect you to /orders/checkout which is intended but sometimes it redirects you to /guidelines-tools/checkout when it shouldn't.

I've noticed a few updates ago you disabled the next buttons in the checkout after the user clicks them once, perhaps you could do this to the "Proceed to checkout" button to fix this.