Hi Jerome!
Just found another small bug, I've just checked the your online demo, it's still in it.
In administrator when vendors are listed on this link (/administrator/index.php?option=com_hikamarket&ctrl=vendor) and I change a vendor is published or not, all the vendor's options (Invoice Number format, Paypal email, Product limitation, Order notification status filter) are deleted, and set back to default. I think this shouldn't be normal.
If there's a fix for that, please give the codelines to change.
Thanks in advance!