Hi,
I see what you want to do and I tried to found a simple solution.
The fact is, it requires modification in the "category type selector" itself ; by adding new parameters in some functions and give you the possibility to use them.
In the same way, it could be interesting to have an option to only select final nodes in the tree.
If you want, I can give you the modifications requires in the file "administrator/com_hikamarket/types/shop_category.php" in order to add your specific option.
With these modifications, you would be able to activate the option directly in the "productmarket | form" view:
Code:
echo $this->categoryType->displayMultiple('data[product][categories]', @$this->product->categories, '', $this->rootCategory /*, THE NEW OPTION HERE */);
By modifying a core file, you will have to be careful with updates, because HikaMarket updates will remove your modifications.
That's why I have to design it correctly and include the patch in HikaMarket too, so you will be compatible with updates (it would replace the file but with the same kind of modifications).
Regards,
