code: @Override
      public boolean affectsDisplay()
      {
          boolean ret = containsFlow();
          //non-zero top or left border
          if (border.top > 0 || border.bottom > 0)
              ret = true;
          //the same with padding
          if (padding.top > 0 || padding.bottom > 0)
              ret = true;
          
          return ret;
      }
docs: Returns true if the element displays at least something