為什麼我的 Java Swing 等待遊標並不總是正確顯示，如何使用玻璃窗格修復它？

import java.awt.*;
import java.awt.event.*;
import java.util.TimerTask;
import java.util.Timer;

public class BusyCursorTest extends javax.swing.JFrame {

    private javax.swing.JPanel cursorPanel = null;

    public BusyCursorTest() {

        // ...

        public static void startWaitCursor(javax.swing.JFrame frame) {
            frame.getGlassPane().setCursor(java.awt.Cursor.getPredefinedCursor(java.awt.Cursor.WAIT_CURSOR));
            frame.getGlassPane().addMouseListener(mouseAdapter);
            frame.getGlassPane().setVisible(true);
        }

        private static void stopWaitCursor(javax.swing.JFrame frame) {
            frame.getGlassPane().setCursor(originalCursor);
            frame.getGlassPane().removeMouseListener(mouseAdapter);
            frame.getGlassPane().setVisible(false);
        }

        // ...
    }

    // ...

    public static java.awt.Cursor originalCursor = null;

    private static final java.awt.event.MouseAdapter mouseAdapter = new java.awt.event.MouseAdapter() {
    };

    public static final int DELAY_MS = 250;
}