Filter products on parent category page

I have displayed all products from subcategories on the parent category page by adding 'filter_sub_category' => true in $filter_data in catalog/controller/product/category.php
Now i have included filter module in the sidebar - however i'm not able to see filters(they display names of the filters with (0))
But when i go to the subcategory page - the filter displays results in parenthesis
Please help
thank you

Are you talking about the built-in OpenCart filter module or some other extension?

Thank you solved now