Pb submitting file for vendor

-- Joomla version -- : 3

Hi

I have a problem when testing the product submission as vendor. I want to add a file (as I share electronic files) and use the drag'n drop field at the bottom of the page.

- my product price is set to 0, this means it is free . But my file is not downloaded even if the price is free.
I have to force the free download to make it correct. But for many vendors that want to make it free this step will be a problem if they don't know the process because they have to click again on the file name to edit it and force.
How to make that the file is automatically free download if the product price is 0 ?

Thank you
CEd

PS : during a vendor submission in a product page in hikamarket after saving I have this notice (note that I disabled the tags for vendor in the rights)
Notice: Undefined index: tags in /home/ckwebcre/public_html/themes-ck/administrator/components/com_hikamarket/classes/product.php on line 114

it tells me
You have the latest stable version of HikaMarket Multivendor: 1.4.4
Your version is 2.3.3, the latest stable version is 2.3.4

so my hikashop is not up to date. I will upgrade.
In I first thought that I had a problem with hikamarket, then it seemed to be into hikashop. As they are imbricated ...
I think that the problem with the 0 price and no download is a hikashop problem