FULL PRODUCT VERSION :


ADDITIONAL OS VERSION INFORMATION :
Ubuntu 11.10 32bit

A DESCRIPTION OF THE PROBLEM :
Run follow test case on Linux with Gnome desktop environment, use tab to navigator between controls, when a ComboBox component gets focused, the out line graphic which indicates focus is not painted.
  To compare the behavior, please run the test case in Nimbus L&F.

Test case

/*
 * Copyright (c) 2012 Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

/*
 * Portions Copyright (c) 2012 IBM Corporation
 */

import java.awt.Container;
import java.awt.GridLayout;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.UIManager;

public class JComboBoxFocusTest extends JFrame {

    JComboBoxFocusTest() {
        setVisible(true);
        setBounds(0, 0, 800, 600);
        
        Container pane = getContentPane();
        pane.setBounds(0, 0, 800, 600);
        pane.setLayout(new GridLayout());

        JButton jb1 = new JButton("Button1");
        jb1.setFocusable(true);
        pane.add(jb1);

        JComboBox comb1 = new JComboBox();
        comb1.addItem("Hello");
        comb1.addItem("world");
        comb1.setFocusable(true);
        pane.add(comb1);

        JButton jb2 = new JButton("Button1");
        jb2.setFocusable(true);
        pane.add(jb2);

        JComboBox comb2 = new JComboBox();
        comb2.addItem("Hello");
        comb2.addItem("world");
        comb2.setFocusable(true);
        pane.add(comb2);
        pane.setFocusCycleRoot(true);

        pack();
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }

    public static void main(String[] args) {
        try {
            UIManager.setLookAndFeel("com.sun.java.swing.plaf.gtk.GTKLookAndFeel");
        } catch (Exception e) {
            System.err
                    .println("This testcase is only valid on GTK environment");
        }
        new JComboBoxFocusTest();
    }
}



REPRODUCIBILITY :
This bug can be reproduced always.