Hello,
i'm using prestashop for a while now, and did not notice any big problems.
However, i got yesterday a client who wishes to order with her mobile phone.
When she added a product to her basket and continued to shopping.
Then she clicks on the basket item in the right corner, and it goes open you can not click on the proceed to checkout button.
The button is not clickable
The next problem is when you can checkout (if you choose go direct to checkout instead of keep shopping) and you want to fill in your data (like name etc,...) and try to scroll to the next fillout space, you gat a whole white page.
You can test it here: https://goo.gl/ejNWCj
Thank you ! and Merry Christmans