Fields not kept when a product is cloned via the 'Copy' button

Hi,

I noticed that when I duplicate a product with the 'Copy' button, I have some fields that are not duplicated (e.g. 'page title', 'alias', 'canonical url', etc.).
What is also strange is that it also copies my French translation (I use Falang) but the fields are correctly retrieved.
It's just in the original product.

I also noticed that there are grey (text font color) and black fields and it is the grey fields that seem to be affected.

So is there a reason for this? Can these fields be duplicated?

Thanks in advance.

I suspected that it was because these were fields that had to remain unique.
And I just didn't think that Hikashop would block the save in case of duplication of this fields. Sorry, it was logical .

EDIT : Couldn't these unkept fields be generated as for example for the product code which becomes {OriginProductCode}__copyXXXXXXXXX?

Brand url is grey but correctly kept (counter-example to what I thought). It's probably because the text areas (type of field) are 'black' and other fields 'grey'.

So everything is ok, thanks for all these informations.