The SpButtonGroup bean is used to provide a set of mutually exclusive choices that appear as radio buttons.
Consistency between the bean and the context is maintained as follows:
When the view is refreshed, the value property of the button selected in a button group will contain the value of the data element associated with that button group. If there is no radio button with this value, any radio button is selected.
When nothing is selected, this bean will fire a DSECoordinationEvent, and the event name will be "SpButtonGroup.nothingSelected".