为什么JTable中的组件被禁用？

Question

如果列类型为JComboBox，我想在JTable单元格中显示ArrayList。我的代码显示JComboBox，但我无法与JComboBox进行互动。我无法打开它看到它有的物品等。

如果你想试试，这是完整的清单。这有什么问题？

package testproj.jtabletest;

import java.awt.BorderLayout;
import java.awt.Component;
import java.util.ArrayList;

import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.event.TableModelEvent;
import javax.swing.event.TableModelListener;
import javax.swing.table.AbstractTableModel;
import javax.swing.table.TableCellRenderer;

public class JTableTest extends AbstractTableModel implements TableCellRenderer{
    private static final long serialVersionUID = 1703021728506400345L;

    public static void main(String[] args) {
        JFrame frame = new JFrame();
        JTable table = new JTable();
        JScrollPane tableHolder = new JScrollPane(table);
        frame.add(tableHolder, BorderLayout.CENTER);
        frame.setVisible(true);
        frame.pack();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JTableTest test = new JTableTest();
        table.setModel(test);
        table.setDefaultRenderer(ArrayList.class, test);
        table.setRowHeight(30);
        table.setRowMargin(4);
    }

    @Override
    public int getRowCount() {
        return 3;
    }
    @Override
    public int getColumnCount() {
        return 4;
    }
    @Override
    public Object getValueAt(int rowIndex, int columnIndex) {
        ArrayList values = new ArrayList();
        values.add(5);
        values.add("TEST");
        values.add(new Object());
        return values;
    }
    @Override
    public boolean isCellEditable(int row, int column){
        return true;
    }
    @Override
    public void setValueAt(Object aValue, int rowIndex, int columnIndex){
        this.fireTableCellUpdated(rowIndex, columnIndex);
    }
    @Override
    public Class getColumnClass(int colIndex){
        return ArrayList.class;
    }

    @Override
    public Component getTableCellRendererComponent(JTable table, Object value,
            boolean isSelected, boolean hasFocus, int row, int column) {
        JComboBox<Object> re = new JComboBox<Object>();
        re.addItem(5);
        re.addItem("TEST");
        re.addItem(new Object());
        re.setEnabled(true);
        return re;
    }
}