code: public Tabs setAjaxBeforeLoadEvent(ITabsAjaxEvent beforeLoadEvent)
  	{
  		this.ajaxEvents.put(TabEvent.beforeLoad, beforeLoadEvent);
  		setBeforeLoadEvent(new TabsAjaxJsScopeUiEvent(this, TabEvent.beforeLoad));
  		return this;
  	}
docs: Sets the call-back for the AJAX beforeLoad event.
  
  @param beforeLoadEvent
  The ITabsAjaxEvent.