Product Grid: Adding 'ID default category'
Instructions for adding a column to your Sc interface, indicating the default category ID for products
Prerequisites
Access the PRO section of the tool to add custom fields:

Ensure you select the right grid : ‘Catalog: Products grids’:

To add the field to the list of available fields for your grids, click on the in the 'Add a field' panel and enter the following information:
What is the field ID?: id_category_default
SC creates the field, you now need to populate the grid with:
In the Advanced Properties panel on the right handside:
- select the menu SQL Select and enter:
return ', prs.id_category_default AS id_category_default';Finally, register the configuration :

Exit the editing window.
The new field is now present in the list of available fields and you can add it to your product grids.