protected void restoreTransientDescendantComponentStates(FacesContext facesContext, Iterator<UIComponent> childIterator, Map<String, Object> state,
            boolean restoreChildFacets)
    {
        while (childIterator.hasNext())
        {
            UIComponent component = childIterator.next();

            // reset the client id (see spec 3.1.6)
            component.setId(component.getId());
            if (!component.isTransient())
            {
                component.restoreTransientState(facesContext, (state == null) ? null : state.get(component.getClientId(facesContext)));                    
                
                Iterator<UIComponent> childsIterator;
                if (restoreChildFacets)
                {
                    childsIterator = component.getFacetsAndChildren();
                }
                else
                {
                    childsIterator = component.getChildren().iterator();
                }
                restoreTransientDescendantComponentStates(facesContext, childsIterator, state, true);
            }
        }

    }
<p class="changed_added_2_1">Override the base class method to
take special action if the method is being invoked when {@link
StateManager#IS_BUILDING_INITIAL_STATE} is true
<strong>and</strong> the <code>rowStatePreserved</code>
JavaBeans property for this instance is <code>true</code>.</p>

<p class="changed_modified_2_1">The additional action taken is to
traverse the descendents and save their state without regard to
any particular row value.</p>

@since 2.1
primefaces/src/main/java/org/primefaces/component/patch/UIDataPatch.java