How to keep your Simulink customizations organized?

Customizations are a practical way to create shortcuts and custom menus, allowing you to be more productive in Simulink. However, it can be hard to keep a clear oversight of the customization implementations. If the number of customizations increases to say 5+, your sl_customization.m will have many sub-functions, or you will have customization M-files scattered across your MATLAB path.
The introduction of a Customizer super- and subclass makes it easy to plug in and remove customizations in Simulink and Stateflow. The structure allows you to scale up the number of customizations without loosing oversight. Also, it facilitates sharing and re-use of customizations.

An example application and more details can be found here:
http://monkeyproofsolutions.nl/en/how-to-keep-your-simulink-customizations-organized/

Note:
The code can be used from R2011b. Earlier releases have not been tested.