在我的应用程序中，我使用jlist和jscrollpane来显示操作日志。为此，我愿意：

logModel = new DefaultListModel();
        logModel.ensureCapacity(300);
        logList = new JList(logModel);
        logList.setPreferredSize(new Dimension(300, 150));
        logList.setVisibleRowCount(6);
        JScrollPane sp = new JScrollPane(logList);
        sp.setHorizontalScrollBar(null);
        GridBagConstraints gbc_logList = new GridBagConstraints();
        gbc_logList.anchor = GridBagConstraints.WEST;
        gbc_logList.gridx = 0;
        gbc_logList.gridy = 6;
        gbc_logList.weightx = 1.0;
        gbc_logList.weighty = 0.5;
        gbc_logList.gridwidth = 3;
        pane.add(sp, gbc_logList);

但如果我开始添加项目，列表中最多只显示9个项目。但是模型报告的大小是正确的（如示例11），我添加了一个序列

private void createFolderSequence() {
        logModel.add(logModel.getSize(), "Create Folder: JNIFolder in root");
        int res = createFolder("JNIFolder", "/");
        logModel.add(logModel.getSize(), "Created: " + Integer.toString(res));

        logModel.add(logModel.getSize(), "Create Folder: JNIFolder2 in /JNIFolder/");
        res = createFolder("JNIFolder2", "/JNIFolder/");
        logModel.add(logModel.getSize(), "Created: " + Integer.toString(res));

        logModel.add(logModel.getSize(), "Rename Folder: JNIFolder2 to NIFolder3");
        res = renameFolder("/JNIFolder/JNIFolder2","JNIFolder3");
        logModel.add(logModel.getSize(), "Renamed: " + Integer.toString(res));

        logModel.add(logModel.getSize(), "Remove Folder: JNIFolder2");
        res = removeFolder("/JNIFolder/JNIFolder2");
        logModel.add(logModel.getSize(), "Removed: " + Integer.toString(res));
        System.out.println(logModel.getSize());

        logModel.add(logModel.getSize(), "Remove Folder: JNIFolder3");
        logModel.add(logModel.getSize(), "Remove Folder: JNIFolder3");
        res = removeFolder("/JNIFolder/JNIFolder3");
        logModel.add(logModel.getSize(), "Removed: " + Integer.toString(res));
        System.out.println(logModel.getSize()); //Print 11

    }

控制台显示最后11，但只有9个项目是在列表中，如果我向下滚动。你知道我做错了什么或错过了什么吗？