docs: protected void filterMarginalSeparators()
      {
          for (Iterator<Separator> it = hsep.iterator(); it.hasNext();)
          {
              Separator sep = it.next();
              if (sep.getY1() == root.getY1() || sep.getY2() == root.getY2())
                  it.remove();
          }
          for (Iterator<Separator> it = vsep.iterator(); it.hasNext();)
          {
              Separator sep = it.next();
              if (sep.getX1() == root.getX1() || sep.getX2() == root.getX2())
                  it.remove();
          }
      }