I'm trying to get Wordpress' Admin Post Page to display some form of output when a specific category (say, 'Featured') is selected.

Something like this (original page):

![original-image](https://i.stack.imgur.com/xvhIC.png)

When I select the 'Featured' category (selected 'Featured' category), I want something to display, like this:

![when-selected](https://i.stack.imgur.com/ev9lA.png)

Meaning the page checks if the specific category is checked, and if it is, Wordpress generates an option menu for the user to fill in.

How do I go about doing this? I'm looking at the Wordpress Codex but so far, no dice.