ZK - Open Source Ajax Java Framework

hai
Assume i have a group box and that group box contains 10 text boxes and some other components .And that group box is visible false
<groupbox visible="false>
<textbox></textbox>
<textbox></textbox>
...
<<textbox></textbox>
'</groupbox>

i want to allocate memory for all textboxes only when groupbox is set to visible other wise
i want to restrict the loading means allocating memory for those components in side groupbox .how can it possible

Please take a look at this guide

Ya fine it is useful content but i want to try like
<groupbox id="groupbox" fufill="onFocus" visible="false"/>
<<textbox id="txtbox></textbox>
</gb>

in my controller
if(flag){
this..groupbox.setVisible(true)
this.groupbox.setFocus(true); //----------here i am keeping focus on it
this.txtbox.setValue("XXX movies are banned "); //here i want to load textbox
}
here i am getting txtbox is null
initially i canot focus on it because it is not visible .how can handle this situation .

Listen on onFulfill event to do the focus and setValue()