MigLayout具有绝对像元坐标和跨度的意外布局

我有一个JPanel，可以在其中动态添加和删除不同大小的子面板。因此，我将MigLayout与绝对单元格坐标一起使用。在以下情况下，结果不是我期望的。

说明问题的我的代码的简化版本如下：

import java.awt.Color;
import java.awt.Dimension;
import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JPanel;
import net.miginfocom.swing.MigLayout;

public class MigLayoutDemo
{
    private static final int CELL_WIDTH = 60;
    private static final int CELL_HEIGHT = 50;

    public static JPanel createBigPanel()
    {
        JPanel bigSubPanel = new JPanel();
        bigSubPanel.setPreferredSize(new Dimension(3 * CELL_WIDTH, 2 * CELL_HEIGHT));      
        bigSubPanel.setBorder(BorderFactory.createLineBorder(Color.black));       
        bigSubPanel.setBackground(Color.LIGHT_GRAY);
        return bigSubPanel;
    }

    public static JPanel createSmallPanel()
    {
        JPanel smallSubPanel = new JPanel();
        smallSubPanel.setPreferredSize(new Dimension(2 * CELL_WIDTH, CELL_HEIGHT));      
        smallSubPanel.setBorder(BorderFactory.createLineBorder(Color.black));     
        smallSubPanel.setBackground(Color.LIGHT_GRAY);
        return smallSubPanel;
    }

    public static JPanel createCellPanel()
    {
        JPanel cellSubPanel = new JPanel();
        cellSubPanel.setPreferredSize(new Dimension(CELL_WIDTH, CELL_HEIGHT));      
        cellSubPanel.setBackground(Color.LIGHT_GRAY);
        return cellSubPanel;
    }

    private static void createAndShowGUI() 
    {
        //Create and set up the window.
        JFrame frame = new JFrame("MigLayoutDemo");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);

        // main panel where the sub-panels are placed in
        JPanel mainPanel = new JPanel();
        MigLayout mg = new MigLayout("debug, gap 0 0");        
        mainPanel.setLayout(mg);

        mainPanel.add(createBigPanel(), "cell 0 0 3 2"); // [col row [span x [span y]]] 
        mainPanel.add(createBigPanel(), "cell 3 0 3 2");
        mainPanel.add(createSmallPanel(), "cell 6 0 2 1, align left top");
        mainPanel.add(createSmallPanel(), "cell 6 1 2 1, align left top");

        mainPanel.add(createSmallPanel(), "cell 0 2 2 1, align left top");
        mainPanel.add(createBigPanel(), "cell 2 2 3 2");       
        // problem occurs
        mainPanel.add(createBigPanel(), "cell 5 2 3 2");

//        mainPanel.add(createCellPanel(), "cell 0 4 1 1");
//        mainPanel.add(createCellPanel(), "cell 1 4 1 1");
//        mainPanel.add(createCellPanel(), "cell 2 4 1 1");
//        mainPanel.add(createCellPanel(), "cell 3 4 1 1");
//        mainPanel.add(createCellPanel(), "cell 4 4 1 1");
//        mainPanel.add(createCellPanel(), "cell 5 4 1 1");
//        mainPanel.add(createCellPanel(), "cell 6 4 1 1");
//        mainPanel.add(createCellPanel(), "cell 7 4 1 1");

        frame.getContentPane().add(mainPanel);
        frame.setResizable(false);
        frame.pack();
    }


    public static void main(String[] args)
    {
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                createAndShowGUI();
            }
        });
    }
}

如果我删除代码行，则mainPanel.add(createBigPanel(), "cell 5 2 3 2");一切都与我预期的一样。但是，当我在第5列和第2行中添加面板时，看起来该面板位于第5列和第6列之间的额外列中。

如果我也添加代码行

mainPanel.add(createCellPanel(), "cell 0 4 1 1");
mainPanel.add(createCellPanel(), "cell 1 4 1 1");
mainPanel.add(createCellPanel(), "cell 2 4 1 1");
mainPanel.add(createCellPanel(), "cell 3 4 1 1");
mainPanel.add(createCellPanel(), "cell 4 4 1 1");
mainPanel.add(createCellPanel(), "cell 5 4 1 1");
mainPanel.add(createCellPanel(), "cell 6 4 1 1");
mainPanel.add(createCellPanel(), "cell 7 4 1 1");

该问题似乎已“解决”，并且所有内容都放置在正确的列和行中。

我怀疑我的问题与细胞的跨度有关。我是否缺少一些MigLayout约束或参数？还是MigLayout库中的错误？

我目前在Java 7中使用MigLayout V4.0。我还使用V5.0快照测试了我的代码，但结果是相同的。