One of his articles covered making your own custom control and it inspired me to make a custom control for showing a certain taxonomy dropdown on the theme customizer. At first, I had just wanted this for the purpose of choosing from a dropdown of categories to use as featured posts in my theme. Then I thought it could really just as well be used for any taxonomy object. Behind the scenes, this control is using the wp_dropdown_categories function, which allows you to build a dropdown of categories (or any other registered taxonomy).
The code for the control really wasn’t bad. After actually implementing this and trying to use it, I found that my changes were not being saved. There is a
data-customize-setting-link attribute that must be appended to your element. Below is the code from my functions.php file and the class being called by functions.php: