http://java.net/jira/browse/MACOSX_PORT-266 submitted 2011/08/11 by Igor Stolyarov
Swing GUI elements placed into container with FlowLayout manager have different baselines.
Test for reproducing issue:
import java.awt.FlowLayout;
import java.awt.Font;
import javax.swing.JCheckBox;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
import javax.swing.JSpinner;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
public class FlowLayoutTest {
    private JComboBox jcb;
    private JRadioButton jrb;
    private JCheckBox jckb;
    private JTextField jtf;
    private JSpinner jsp;
    private boolean status = false;
    public FlowLayoutTest() throws Exception {
        SwingUtilities.invokeAndWait(new Runnable() {
            @Override
            public void run() { createAndShowGUI(); }
        });
    }
    private void createAndShowGUI() {
        JFrame frame = new JFrame("FlowLayout Test");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        JPanel panel = new JPanel();
        FlowLayout layout = new FlowLayout();
        layout.setAlignOnBaseline(true);
        panel.setLayout(layout);
        jcb = new JComboBox(new String[]{"red", "yellow", "green"});
        jcb.setFont(new Font("Monospaced", Font.PLAIN, 12));
        jrb = new JRadioButton("Radio Button");
        jrb.setFont(new Font("Times New Roman", Font.BOLD, 10));
        jckb = new JCheckBox("Check Box");
        jckb.setFont(new Font("Sans Serif", Font.BOLD, 25));
        jtf = new JTextField("Hello World!", 40);
        jtf.setFont(new Font("Times New Roman", Font.BOLD, 10));
        jsp = new JSpinner();
        jsp.setFont(new Font("Times New Roman", Font.BOLD, 40));
        panel.add(jrb);
        panel.add(jckb);
        panel.add(jcb);
        panel.add(jtf);
        panel.add(jsp);
        frame.getContentPane().add(panel);
        frame.doLayout();
        frame.pack();
        frame.setVisible(true);
    }
    public void test() throws Exception {
        SwingUtilities.invokeAndWait(new Runnable() {
            @Override
            public void run() { int x = jcb.getBaseline(jcb.getWidth(), jcb.getHeight()) + jcb.getY(); int y = jtf.getBaseline(jtf.getWidth(), jtf.getHeight()) + jtf.getY(); int z = jckb.getBaseline(jckb.getWidth(), jckb.getHeight()) + jckb.getY(); int a = jrb.getBaseline(jrb.getWidth(), jrb.getHeight()) + jrb.getY(); int b = jsp.getBaseline(jsp.getWidth(), jsp.getHeight()) + jsp.getY(); status = x == y && x == z && x == a && x == b; }
        });
    }
    public int checkStatus() {
        if(status) { System.out.println("TEST PASS!"); return 0; }
        System.out.println("TEST FAIL!");
        return 1;
    }
    public static void main(String[] argv) throws Exception { FlowLayoutTest test = new FlowLayoutTest(); test.test(); System.exit(test.checkStatus()); }
}