protected void saveDescendantState() {

        FacesContext context = getFacesContext();
        if (getChildCount() > 0) {
            for (UIComponent kid : getChildren()) {
                if (kid instanceof UIColumn) {
                    saveDescendantState(kid, context);
                }
            }
        }

    }
<p>Save state information for all descendant components, as described for
<code>setRowIndex()</code>.</p>
primefaces/src/main/java/org/primefaces/component/patch/UIDataPatch.java