private void ensureColumns(List<List<ResultCell>> data) {
for (List<ResultCell> row : data) {
for (final ResultCell cell : row) {
if (!colMap.containsKey(cell.getTitle())) {
SortableColumn<List<ResultCell>, SafeHtml> column =
new SortableColumn<List<ResultCell>, SafeHtml>(new SafeHtmlCell()) {
@Override
public SafeHtml getValue(List<ResultCell> cells) {
ResultCell c = lookupCell(cell.getTitle(), cells);
SafeHtmlBuilder sb = new SafeHtmlBuilder();