FULL PRODUCT VERSION :
java version "1.5.0_07"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_07-b03)
Java HotSpot(TM) Client VM (build 1.5.0_07-b03, mixed mode, sharing)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows 2000 [Version 5.00.2195]

A DESCRIPTION OF THE PROBLEM :
After enabling row selection in JTable with setRowSelectionAllowed(true) the whole row should be repainted whenever the JTable loses focus, since it makes sense to paint the row with a different background color.
Unfortunately only the cell that was clicked on when the row was selected is repainted. It seems that in BasicTableUI.Handler the code taking rowSelection mode into account is simply missing. The bulk of the missing code can probably be copied from the corresponding selection change methods (e.g. JTable#columnSelectionChanged(...)).

This bug is not obvious, because of bug 5105921
Java 5 on Mac OS X does not exhibit this bug.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Compile and start the test code with: java Main

1) The code will show a window with a textfield and a 2 x 2 table. All rows are red, since no row is selected.
2) Now select a row by clicking on one of the table cells.
3) The whole row becomes blue, since all cells in the row are repainted.

The test code writes a couple of statements to the console, indicating which cells are repainted.

4) Now click into the textfield.

The cell you previously clicked on becomes green - as expected since
the table lost focus. However, the other cell in the same row stays
blue, since it is not repainted.

I am of the opinion that the whole row should be repainted when row
selection is allowed and the table loses focus, since many OS
actually paint the table background in different colors depending on
whether the table has the focus or not. Note that this is independent
of the question whether the individual cell has the focus or not.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The colors of the whole row should change when the JTable loses focus.
ACTUAL -
Only the colors of the last selected cell changes when the JTable loses focus.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------

import javax.swing.*;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.DefaultTableCellRenderer;
import java.awt.*;

public class Main extends JFrame {

     public Main() throws HeadlessException {
         setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         final Container contentPane = getContentPane();
         final JTable table = new JTable();
         contentPane.setLayout(new BorderLayout());
         contentPane.add(new JTextField(), BorderLayout.NORTH);
         contentPane.add(table, BorderLayout.CENTER);
         table.setRowSelectionAllowed(true);
         final DefaultTableModel tableModel = new DefaultTableModel
(new Object[][] {new Object[]{1, 2}, new Object[]{3, 4}}, new Object[]
{1, 2});
         table.setDefaultRenderer(Object.class, new
DefaultTableCellRenderer() {
             public Component getTableCellRendererComponent(JTable
table, Object value, boolean isSelected, boolean hasFocus, int row,
int column) {
                 System.out.println("Getting Renderer for row=" + row
+ ", col=" + column);
                 if (isSelected) {
                    super.setBackground(Color.BLUE);
                 } else {
                     super.setBackground(Color.RED);
                 }
                 final Component permanentFocusOwner =
KeyboardFocusManager.getCurrentKeyboardFocusManager
().getPermanentFocusOwner();
                 if (isSelected && permanentFocusOwner != table &&
permanentFocusOwner != table.getEditorComponent()) {
                    super.setBackground(Color.GREEN);
                 }
                 setFont(table.getFont());
                 setValue(value);
                 return this; }
         });
         table.setModel(tableModel);
         setSize(500, 500);
         setVisible(true);
     }

     public static void main(String[] args) throws
IllegalAccessException, UnsupportedLookAndFeelException,
InstantiationException, ClassNotFoundException {
         UIManager.setLookAndFeel
(UIManager.getSystemLookAndFeelClassName());
         SwingUtilities.invokeLater(new Runnable(){
             public void run() {
                 new Main();
             }
         });
     }
}
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
You can probably write your own focuslistener that repaints the whole row when the rowSelectionAllowed flag is set.