This is Win32 specific problem.

Vertical position of a LightWeightCompoent is computed
incorrectly when the componet is added to a Frame. Insets (for a title
bar) is disregarded from the comutation. Due to this arithmetic error,
effect of MouseEvent.MOUSE_ENTERED, for example, is positioned slightly
differently than expected (vertically).


A sample program to cause this error is attached below.

import java.awt.*;
import java.awt.event.*;


public class Test extends Frame implements Runnable, ActionListener {

        TestContainer southContainer;
        TestContainer centerContainer;
        TestButton button1;
        TestButton button2;
        TextArea messageBox;
        Thread thread;
        int counter;

        public Test() {
                super();
                String[] fontList =
Toolkit.getDefaultToolkit().getFontList();
                setFont(new Font(fontList[0], Font.BOLD, 16));
                setLayout(new BorderLayout());
                button1 = new TestButton("click to continue");
                button1.addActionListener(this);
                button2 = new TestButton("more information");
                button2.addActionListener(this);
                messageBox = new TextArea("Message Box", 4, 12,
TextArea.SCROLLBARS_NONE);
                centerContainer = new TestContainer();
                centerContainer.setLayout(new
FlowLayout(FlowLayout.CENTER, 16,
16));
                centerContainer.add(messageBox, BorderLayout.CENTER);
                add(centerContainer, BorderLayout.CENTER);
                southContainer = new TestContainer();
                southContainer.setLayout(new
FlowLayout(FlowLayout.CENTER, 16,
16));
                southContainer.add(button1);
                southContainer.add(button2);
                add(southContainer, BorderLayout.SOUTH);
                enableEvents(AWTEvent.WINDOW_EVENT_MASK);
                pack();
                counter = 0;
                thread = new Thread(this);
                thread.start();
        }

        public static void main(String[] arg) {
                new Test().setVisible(true);
        }

        protected void processWindowEvent(WindowEvent e) {
                if (e.getID() == e.WINDOW_CLOSING) {
                        System.exit(0);
                }
        }

        public void actionPerformed(ActionEvent e) {
                if (e.getSource() == button1) {
                        System.exit(0);
                }
        }

        public void update(Graphics g) {
                paint(g);
        }

        public void paint(Graphics g) {
                drawFace(g);
                if (button1 != null) {
                        button1.drawFace();
                }
                if (button2 != null) {
                        button2.drawFace();
                }
        }

        public void run() {
                while (true) {
                        try {
                                thread.sleep(200);
                        } catch(InterruptedException e) {
                                thread.stop();
                                break;
                        }
                        counter = (counter + 2) % 20;
                        repaint();
                }
        }

        protected void drawFace(Graphics g) {
                Dimension s = getSize();
                for (int i = counter; i < Math.max(s.width, s.height) *
2; i +=
20) {
                        g.setColor(getBackground());
                        g.drawLine(i , 0, 0, i );
                        g.setColor(getForeground());
                        g.drawLine(i + 2, 0, 0, i + 2);
                }
        }

}


class TestContainer extends Container {

        public TestContainer() {
                super();
        }

}


class TestButton extends Component {

        String text;
        boolean state;
    ActionListener actionListener;

        public TestButton(String text) {
                super();
                this.text = text;
                state = false;
                enableEvents(AWTEvent.MOUSE_EVENT_MASK);
        }

        protected void processMouseEvent(MouseEvent e) {
                switch (e.getID()) {
                  case e.MOUSE_ENTERED:
                        state = true;
                        drawFace();
                        break;
                  case e.MOUSE_EXITED:
                        state = false;
                        drawFace();
                        break;
                  case e.MOUSE_RELEASED:
                        processEvent(new ActionEvent(this,
ActionEvent.ACTION_PERFORMED, text));
                        break;
                }
        }

        protected void processEvent(AWTEvent e) {
                if (e instanceof ActionEvent) {
                        processActionEvent((ActionEvent)e);
                        return;
                }
                super.processEvent(e);
        }

        protected void processActionEvent(ActionEvent e) {
                if (actionListener != null) {
                        actionListener.actionPerformed(e);
                }
        }

        public void drawFace() {
                Graphics g = getGraphics();
                if (g != null) {
                        Dimension size = getSize();
                        FontMetrics fm = g.getFontMetrics();
                        int w = fm.stringWidth(text);
                        if (state) {
                                g.setColor(Color.red);
                        }
                        g.drawString(text, (size.width -
fm.stringWidth(text)) /
2, (size.height - fm.getHeight()) / 2 + fm.getAscent());
                        g.drawRect(0, 0, size.width - 1, size.height -
1);
                        g.drawRect(1, 1, size.width - 3, size.height -
3);
                        g.dispose();
                        g = null;
                }
        }

        public void addActionListener(ActionListener l) {
                actionListener = AWTEventMulticaster.add(actionListener,
l);
        }

        public void removeActionListener(ActionListener l) {
                actionListener =
AWTEventMulticaster.remove(actionListener, l);
        }

        public Dimension getMinimumSize() {
                return getPreferredSize();
        }

        public Dimension getPreferredSize() {
                return getMaximumSize();
        }

        public Dimension getMaximumSize() {
                Graphics g = getGraphics();
                Dimension size;
                if (g != null) {
                        FontMetrics fm = g.getFontMetrics();
                        size = new Dimension(fm.stringWidth(text) + 16,
fm.getHeight() + 16);
                        g.dispose();
                        g = null;
                } else {
                        size = new Dimension(16, 16);
                }
                return size;
        }

}