Thank yo, Sir!

I have figured out the official Enfold way to adapt this kind of function:

Copy to function.php :

// Adding Featured Image in CPTs' List | Github: @foldesistudio | foldesistudio.hu
# portfolio_columns, register_post_type then append _columns
	add_filter( 'manage_edit-application_columns', 'prod_edit_columns' );
	add_filter( 'manage_edit-document_columns', 'prod_edit_columns' );
	add_filter( 'manage_edit-scholarship_columns', 'prod_edit_columns' );
	add_filter( 'manage_edit-regulation_columns', 'prod_edit_columns' );