private TableCell toTableCell()
    {
        TableCell tc = new TableCell("td", null);
        String className = null;
        if ( isBase && nested )
            className = "base";
        for ( int i=0;i<fragments.size();i++ )
        {
            Atom a = fragments.get(i);
            if ( className == null && a instanceof Fragment )
                className = ((Fragment)a).getClassName();
            if ( a instanceof Fragment )
                tc.add( ((Fragment)a).contents, className );
            else
                tc.add( a.toString() );
            // reset
            if ( className != null && !className.equals("base") )
                className = null;
        }
        tc.setID( id );
        return tc;
    }