Adding a Custom Column to the Ad listing post list
I'm trying to add a custom column to the Ads Listing page in the admin panel.
I've been able to add the column to all other places such as the Coupon listing page in the admin panel using:
manage_discount_coupon_posts_columns
manage_discount_coupon_posts_custom_column
However this code:
manage_ad_listing_coupon_posts_columns
manage_ad_listing_posts_custom_column
does not work for the ad listing columns, and having read around the subject I'm still struggling for a solution....