Since ofUI is deprecated I quickly wanted to port some of the ofUI elements to ofxGui.
The code and all the details you need to know:
I have been building this in order to use it for my VJ program SPLASH. Here are screenshots that show how SPLASH looked like during the development of the addon. I simply like the process visible in these images. It should also give you an idea of how complex GUIs can be that you build with ofxGuiExtended.
This little addons can give controls like toggles and sliders the role to be master or slave controls. You can assign a master to control the slaves value.
Download it here: https://github.com/frauzufall/ofxMasterSlaveControl
This addon will not be merged into ofxGui as originally planned and is now standalone without depending on other addons. Here are some links to the discussions leading to the decision.