FULL PRODUCT VERSION :
Java(TM) SE Runtime Environment (build 1.6.0-rc-b94)


A DESCRIPTION OF THE PROBLEM :
I am uncertain if this is bug or not but I was doing some BasicUI work and it struck me as something odd. If the user is dragging a column to the left, the undragged column to the right does not have a vertical line. Its flush with the gray border. So cells have the appearance of:
*****
       *
       *
*****

In the test case, notice how the column with the negative dragged distance(column 3) is next to a column that lacks a vertical line(column 4). Notice that the positive dragged column does not have the column to the left, missing its vertical line. So at the minimum, its inconsistent.


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Run this test, look at the vertical lines around the gray area.


EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
vertical lines drawn
ACTUAL -
a missing vertical line when dragged distance was negative.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import javax.swing.*;
import javax.swing.table.*;
import java.awt.*;


public class ShowJTableLineDrawBug implements Runnable{

    public void run(){
        JTable jt = new JTable();
        JTabbedPane jtp = new JTabbedPane();
        jtp.addTab("col 3, -10 distance", createJTable(3, -10));
        jtp.addTab("col 3, 10 distance", createJTable(3, 10));
        JFrame jf = new JFrame();
        jf.add(jtp);
        jf.setSize(500,500);
        jf.setVisible(true);

    }

    JPanel createJTable(int col, int distance){

        JPanel panel = new JPanel(new BorderLayout());
        Object[][] data = new Object[30][10];
        Object[] names = new Object[10];
        for(int i = 0; i < 30; i ++){
            if(i < 10)
                names[i] = String.valueOf(i);
            for(int j = 0; j < 10; j ++)
data[i][j] = String.valueOf(j + i);
        }
        DefaultTableModel dtm = new DefaultTableModel(data, names);
        JTable jt = new JTable(dtm);
        JTableHeader header = jt.getTableHeader();
        TableColumnModel tcm = header.getColumnModel();
        header.setDraggedColumn(tcm.getColumn(col));
        header.setDraggedDistance(distance);
        JScrollPane jsp = new JScrollPane(jt);
        panel.add(jsp);
        return panel;
    }






    public static void main(String ... args){
        SwingUtilities.invokeLater(new ShowJTableLineDrawBug());
    }

}
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
user may have to override paintComponent and draw his own vertical line.