Hi,
1.
nicolas wrote: If you want to reset all customizations of views, the simplest is the rename the folder templates/YOUR_TEMPLATE/html/com_hikashop via FTP. That will remove all cusotmizations to all the views that were done via the Display->Views interface.
Then you can see if it helps.
Did you renamed this folder ? Note that you can also test it with another template that you didn't modified.
2. The order_product table is the table where we list all the products that are attached to your order, if you have cleared it, you won't have any product attached to your old orders, but if it's working fine with your new orders, I don't think that you'll have any other issue.
3. Can you tell me what do you exactly means by the PDF layout form ?
PS: Sorry for the delay in our answer, it's a busy week
.