code: private void restoreDescendantState() {
  
          FacesContext context = getFacesContext();
          if (getChildCount() > 0) {
              for (UIComponent kid : getChildren()) {
                  if (kid instanceof UIColumn) {
                      restoreDescendantState(kid, context);
                  }
              }
          }
  
      }
docs: <p>Restore state information for all descendant components, as described
  for <code>setRowIndex()</code>.</p>