Scrollable Tabs don't appear with JDK7 Synth based LaF, different from Java 5/6

FULL PRODUCT VERSION :
java version "1.7.0-ea"
Java(TM) SE Runtime Environment (build 1.7.0-ea-b136)
Java HotSpot(TM) Client VM (build 21.0-b06, mixed mode, sharing)


A DESCRIPTION OF THE PROBLEM :
When a JTabbedPane is configured to display tabs in scrollable mode (tabbedPane.setTabLayoutPolicy(JTabbedPane.SCROLL_TAB_LAYOUT)), only the tab text appears. The tabs are not painted - no background appears.


REGRESSION. Last worked in version 6u24

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Configure tabbed pane for scrollable mode:
tabbedPane.setTabLayoutPolicy(JTabbedPane.SCROLL_TAB_LAYOUT)


EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Tab background should be painted.
ACTUAL -
No tab background is painted.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.awt.Component;
import java.awt.Container;
import java.awt.Label;
import java.util.ArrayList;
import java.util.List;

import javax.swing.Icon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTabbedPane;
import javax.swing.UIManager;

public class ScrollableTabbedPaneTest extends JFrame
{
  public static void main(String[] args) throws Exception
  {
    UIManager.setLookAndFeel("com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel");
    new ScrollableTabbedPaneTest();
  }
  
  public ScrollableTabbedPaneTest() throws Exception
  {
    super("ScrollableTabbedPane Test");
    JTabbedPane tabbedPane = new JTabbedPane();
    tabbedPane.setTabLayoutPolicy(JTabbedPane.SCROLL_TAB_LAYOUT);
    
    Icon icon = UIManager.getIcon("Tree.closedIcon");
    for (int i = 1; i<20; i++)
      tabbedPane.addTab("Tab" + i, icon, new Label("Pane"+i));
    add(tabbedPane);
        
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setSize(400, 300);
    setLocationRelativeTo(null);
    setVisible(true);
  }
  
}
---------- END SOURCE ----------