tringBuilder(style.header());
      if (isFirst) {
        classesBuilder.append(" " + style.firstColumnHeader());
      }
      if (isLast) {
        classesBuilder.append(" " + style.lastColumnHeader());
      }
      if (column.isSortable()) {
        classesBuilder.append(" " + style.sortableHeader());
      }
      if (isSorted) {
        classesBuilder.append(" "
            + (isSortAscending ? style.sortedHeaderAscending() : style.sortedHeaderDescending()));
      }

      // Create the table cell.
