code: protected AjaxEventBehavior newAjaxEventBehavior(final String event)
  	{
  		return new AjaxEventBehavior(event)
  		{
  			private static final long serialVersionUID = 1L;
  
  			@Override
  			protected void onEvent(final AjaxRequestTarget target)
  			{
  				final RadioGroup<T> radioGroup = getGroup();
  				radioGroup.processInput();
  				onClick(target);
  			}
  
  			@Override
  			protected void updateAjaxAttributes(final AjaxRequestAttributes attributes)
  			{
  				super.updateAjaxAttributes(attributes);
  				AjaxRadio.this.updateAjaxAttributes(attributes);
  			}
  		};
  	}
docs: New ajax event behavior.
  
  @param event
  the name of the default event on which this link will listen to
  @return the ajax behavior which will be executed when the user clicks the link