Extensions are one of the most powerful features of Redux. Any part of Redux can be overloaded to do ANYTHING with extensions.
RUN BEFORE YOU CONFIG FILE
For extensions to work, you MUST run the extension loader and any config files BEFORE your options panel code. Otherwise it will not be applied. A limitation of WordPress hooks I fear. 😉
To make this easy as can be, we’ve setup a repo for our extensions loader. You can grab that code here: https://github.com/ReduxFramework/redux-extensions-loader
If you wanted to get started faster, use the Redux Generator found here: http://generate.reduxframework.com/. It will generate for you code allowing you to start however you may need and also customize the function calls so you can sure you won’t have crossover with other devs.
Make a Custom Extension
You can make your own custom extension. In fact, if you want to change the way a Redux field does something, you should ALWAYS use an extension instead of modifying the core. We’ve set up a repo for that too. Grab it here: https://github.com/ReduxFramework/extension-boilerplate.