int h = (rowHeight + rowMargin); int delta = h * direction;
  public int getScrollableUnitIncrement(Rectangle visibleRect, int orientation, int direction)  {    // FIXME: I don't exactly know what sun does here. in both cases they    // pick values which do *not* simply expose the next cell in a given    // scroll direction.    if (orientation == SwingConstants.VERTICAL)      return direction * rowHeight;    else      {        int sum = 0;        for (int i = 0; i < getColumnCount(); ++i)          sum += columnModel.getColumn(0).getWidth();        int inc = getColumnCount() == 0 ? 10 : sum / getColumnCount();        return direction * inc;      }  }