I'm trying to figure out how to make it so that when you select a parent post category in a new post, all of the subcategories will be automatically selected as well.
Example: If the parent category is Fruit, and the subcategories include the names of different types of fruit, when I write a post about the much broader category of Fruit and select "Fruit" as my category, all of the individual types of fruit that have been named as categories within the Fruit category will be selected too... kind of like making the Fruit category become a "select all subcategories" button.
I am using WordPress version 3.8 and a Twenty Twelve child theme.