为什么JComboBox没有显示其默认项目和右侧的箭头，而是指向下方的箭头？

Question

在我用Java创建的Window 95模拟器的“位置信息”JDialog中，在“你现在在哪个国家？”的问题下面有一个JComboBox。

为什么JComboBox没有显示其默认项和右侧的箭头？JComboBox中有一个指向下方的箭头。

以下是位置信息JDialog中包含的对象的相关代码片段:

////Location Information Objects
locationInformationCountrySelect = new JComboBox < String > ();
locationInformationCountrySelect.addItem("United States of America (1)");
locationInformationCountrySelect.addItem("United States Virgin Islands (1)");
locationInformationCountrySelect.addItem("Uruguay (598)");
locationInformationCountrySelect.addItem("Uzekistan (7)");
locationInformationCountrySelect.addItem("Vanuatu (678)");
locationInformationCountrySelect.addItem("Vatican City (39)");
locationInformationCountrySelect.setBounds(230, 150, 500, 30);
locationInformationCountrySelect.setSelectedIndex(0);
locationInformationImage = new JLabel(new ImageIcon(getClass().getClassLoader().getResource("LocationInformationImage.png")));
locationInformationCountry = new JLabel(new ImageIcon(getClass().getClassLoader().getResource("LocationInformationCountry.png")));
locationInformationAreaCode = new JLabel(new ImageIcon(getClass().getClassLoader().getResource("LocationInformationAreaCode.png")));
locationInformationAccessNumber = new JLabel(new ImageIcon(getClass().getClassLoader().getResource("LocationInformationAccessNumber.png")));
locationInformationPhoneSystem = new JLabel(new ImageIcon(getClass().getClassLoader().getResource("LocationInformationPhoneSystem.png")));
locationInformationSeparator = new JLabel(new ImageIcon(getClass().getClassLoader().getResource("LocationInformationSeparator.png")));
locationInformationImage.setBounds(20, 20, 200, 400);
locationInformationCountry.setBounds(230, 20, 580, 112);
locationInformationAreaCode.setBounds(230, 220, 448, 37);
locationInformationAccessNumber.setBounds(230, 300, 579, 39);
locationInformationPhoneSystem.setBounds(230, 380, 433, 39);
locationInformationAreaCodeTextField = new JTextField();
locationInformationAccessNumberTextField = new JTextField();
locationInformationAreaCodeTextField.setBounds(230, 265, 100, 33);
locationInformationAccessNumberTextField.setBounds(230, 345, 100, 33);
toneDialing = new JRadioButton("Tone dialing");
pulseDialing = new JRadioButton("Pulse dialing");
toneDialing.setBounds(235, 420, 100, 20);
pulseDialing.setBounds(365, 420, 100, 20);
locationInformationButtonGroup = new ButtonGroup();
locationInformationButtonGroup.add(toneDialing);
locationInformationButtonGroup.add(pulseDialing);

Answer 1

只是一个猜测，因为可能有很多因素。。。

您是否在JavaSwing应用程序中使用Windows外观和感觉？如果您没有切换并保持默认外观和感觉（我认为是Metal），您是否会感知到相同的行为？

如果您在Oracle JDK上运行，是否仍然看到相同的行为？