deactivate Ajax in checkout page

hello
how to deactivate Ajax in checkout page (Shopping Cart)
when scroll down the page, the shopping cart moved to the middle of the page, And prevents the write address.
i Want Shopping Cart (in checkout page), on the side page is fixed.
image from my checkout page (Shopping Cart).

To solve this problem, what should I do?
i use Persian storefront.
my site: https://www.padary.ir
thanks