code: public void addButtonRow()
      {
          buttons=new Composite();
          
          if (!extendRow)
          {
              column.newRow();
              column.addCell(buttons).left().middle();
              column.cell().attribute("colspan","2");
          }
          extendRow=false;
      }
docs: /* add a new button row.
  A button row is a line of a column in a table form where multiple
  buttons can be placed, that is aligned with the left hand side of the
  TableForm Subsequent calls to addButton will
  add buttons to this area.