code: public Tabs setAjaxActivateEvent(ITabsAjaxEvent activateEvent)
  	{
  		this.ajaxEvents.put(TabEvent.activate, activateEvent);
  		setActivateEvent(new TabsAjaxJsScopeUiEvent(this, TabEvent.activate));
  		return this;
  	}
docs: Sets the call-back for the AJAX activate event.
  
  @param activateEvent
  The ITabsAjaxEvent.