Name: dbT83986 Date: 01/10/99


The very first time the popup menu for a JCombobox is mapped,
regardless of the Look&Feel, the bottom one or two pixels are
missing. After the first time the menu is drawn correctly.

The following code will demonstrate the problem:

//~~~~~~~~~~~~~~~~~~~~~~~~ cut here ~~~~~~~~~~~~~~~~~~~~~~~~~~
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class comboboxBug extends JPanel {
    static JFrame frame;

    static String metal= "Metal";
    static String metalClassName = "javax.swing.plaf.metal.MetalLookAndFeel";

    static String motif = "Motif";
    static String motifClassName =
            "com.sun.java.swing.plaf.motif.MotifLookAndFeel";

    static String windows = "Windows";
    static String windowsClassName =
            "com.sun.java.swing.plaf.windows.WindowsLookAndFeel";

    JRadioButton metalButton, motifButton, windowsButton;

    public comboboxBug() {

        String fruitChoices[] = {"Apple", "Banana", "Cherry", "Fig", "Grape", "Watermelon"};
        JComboBox fruits = new JComboBox(fruitChoices);
        fruits.setMaximumRowCount(4);

        metalButton = new JRadioButton(metal);
        metalButton.setActionCommand(metalClassName);

        motifButton = new JRadioButton(motif);
        motifButton.setActionCommand(motifClassName);

        windowsButton = new JRadioButton(windows);
        windowsButton.setActionCommand(windowsClassName);

        // Group the radio buttons.
        ButtonGroup group = new ButtonGroup();
        group.add(metalButton);
        group.add(motifButton);
        group.add(windowsButton);

        // Register a listener for the radio buttons.
        RadioListener myListener = new RadioListener();
        metalButton.addActionListener(myListener);
        motifButton.addActionListener(myListener);
        windowsButton.addActionListener(myListener);

        add(fruits);
        add(metalButton);
        add(motifButton);
        add(windowsButton);
    }


    /** An ActionListener that listens to the radio buttons. */
    class RadioListener implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            String lnfName = e.getActionCommand();

            try {
                UIManager.setLookAndFeel(lnfName);
                SwingUtilities.updateComponentTreeUI(frame);
                frame.pack();
            }
            catch (Exception exc) {
                JRadioButton button = (JRadioButton)e.getSource();
                button.setEnabled(false);
                updateState();
                System.err.println("Could not load LookAndFeel: " + lnfName);
            }
            
        }
    }

    public void updateState() {
         String lnfName = UIManager.getLookAndFeel().getClass().getName();
         if (lnfName.indexOf(metal) >= 0) {
             metalButton.setSelected(true);
         } else if (lnfName.indexOf(windows) >= 0) {
             windowsButton.setSelected(true);
         } else if (lnfName.indexOf(motif) >= 0) {
             motifButton.setSelected(true);
         } else {
             System.err.println("SimpleExample is using an unknown L&F: " + lnfName);
         }
    }

    public static void main(String s[]) {

        comboboxBug panel = new comboboxBug();
        
        frame = new JFrame("Combobox Menu Bug");
        frame.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {System.exit(0);}
        });
        frame.getContentPane().add(panel);
        frame.pack();
        frame.setVisible(true);
        
        panel.updateState();
    }
}
(Review ID: 52358)
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