down.setCellRenderer(new DownTableCellRenderer());
down.setComparator(new GeneralComparator("isDown"));
table_columns.add(down);
super.buildColumns(new ServerListTableModel());
//TableColumnModel server_tab_column_model = new DefaultTableColumnModel();
//for(TableColumnExt column : table_columns) {
// server_tab_column_model.addColumn(column);