For sophisticated pages, the performance can be improved if we defer the creation of child components until they are becoming visible. The simplest way to do it is by use of the fulfill attribute. In the following example, the children of the second tab panel are created only if it becomes visible. Refer to the Load on Demand section in the ZK User Interface Markup Language chapter.

<tabbox>
    <tabs>    
        <tab label="Preload" selected="true"/>        
        <tab id="tab2" label="OnDemand"/>        
    </tabs>    
    <tabpanels>    
        <tabpanel>        
    This panel is pre-loaded since no fulfill specified    
        </tabpanel>        
        <tabpanel fulfill="tab2.onSelect">        
    This panel is loaded only tab2 receives the onSelect event    
        </tabpanel>        
    </tabpanels>    
</tabbox>