JTable column width resizing woe

If I put JTables in JScrollPanes, column width resizing does work
as expected. But if JTables are simply put in simpler containers
like JPanels, resizing behavior is quite abnormal. What could be
the cause of the problem and its workaround?

Here's a small test program:

import java.awt.*;
import java.beans.*;
import java.util.*;
import javax.swing.*;
import javax.swing.table.*;
import javax.swing.event.*;

public class TableColumnWidthResize{
 JFrame frame;
 JTable t1, t2;
 TableColumnModel tcm1, tcm2;
 Enumeration columns1, columns2;

 String[] t1h = {"Road", "Length", "City"};
 String[][] t1c
  = {{"NW2", "800", "Dora"},
    {"Iban", "600", "Weiho"},
    {"ENE2", "500","Porso"}};
 String[] t2h = {"Flower", "Curse", "Priest"};
 String[][] t2c
   = {{"Fang", "7.00", "EggChar"},
     {"Shaoma", "5.00", "ScaCra"},
     {"Jiao", "4.00", "PorCabb"}};

 public TableColumnWidthResize(){
   frame = new JFrame();

   frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
   Container con = frame.getContentPane();
   con.setLayout(new GridLayout(2, 1));

   t1 = new JTable(t1c, t1h); //target table
   t2 = new JTable(t2c, t2h); //source table
   t1.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
   t2.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
   /* you can compare two */
   useScrollPane(t1, t2, con);//works fine(container size weird)
//    nouseScrollPane(t1, t2, con); //resize behavior weird

   frame.pack();
   frame.setVisible(true);

   tcm1 = t1.getColumnModel();
   tcm2 = t2.getColumnModel();
   columns2 = tcm2.getColumns(); // all columns of t2

   TableColumnListener tcl = new TableColumnListener();
   while (columns2.hasMoreElements()){
     TableColumn tc = (TableColumn)(columns2.nextElement());
     tc.addPropertyChangeListener(tcl);
   }
 }

 class TableColumnListener implements PropertyChangeListener{
   // achieve 'twin-resizing' of two tables
   public void propertyChange(PropertyChangeEvent pce){
     TableColumn tc = (TableColumn)(pce.getSource());
     int i = tc.getModelIndex();
     tcm1.getColumn(i).setPreferredWidth(tc.getWidth());
   }
 }

 void useScrollPane(JTable ta, JTable tb, Container c){
   JScrollPane jsc1 = new JScrollPane(ta);
   JScrollPane jsc2 = new JScrollPane(tb);
   c.add(jsc1); c.add(jsc2);
 }

 void nouseScrollPane(JTable ta, JTable tb, Container c){
   JPanel p1 = new JPanel(); JPanel p2 = new JPanel();
   p1.setLayout(new BorderLayout());
   p2.setLayout(new BorderLayout());
   p1.add(ta.getTableHeader(), BorderLayout.PAGE_START);
   p2.add(tb.getTableHeader(), BorderLayout.PAGE_START);
   p1.add(ta, BorderLayout.CENTER);
   p2.add(tb, BorderLayout.CENTER);    
   c.add(p1); c.add(p2);
 }

 public static void main(String[] args){
   new TableColumnWidthResize();
 }
}