/**
* Creates a new radiobutton
*/
public CRadioButton() {
super( null );
init( new CommonSimpleRadioAction( this ));
intern().addSelectableListener( new SelectableDockActionListener(){
public void selectedChanged( SelectableDockAction action, Set<Dockable> dockables ) {
if( isSelected() && group != null )
group.selected( CRadioButton.this );
}