This demonstrates the flexible layout capabilities of the CheckboxGroup and RadioGroup classes. It also shows that you can validate checkboxes/radios as a group — try submitting the form before changing any values to see this.
This illustrates the cascading configuration fieldDefaults. At the Panel level, it sets the field label
color to green, so all ancestor fields have green labels.
The js is not minified so it is readable. See check-radio.js.