使用MigLayout在JDialog中进行Pack（）行为

Question

我使用MigLayout创建了简单的Jdialog。一旦actionListener刷新屏幕对话框就会增长。在示例代码中，使用“应用”按钮会更改对话框的大小。

我尝试调试此问题，发现pack（）从MyDialog的LayoutManager获取首选大小，而不是我为内容窗格创建的MigLayout。我用这段代码做了一些非常愚蠢的事吗？

import net.miginfocom.swing.MigLayout;

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.lang.reflect.InvocationTargetException;

public class MigTest {
    public static void main(String[] args) throws InvocationTargetException, InterruptedException {
        EventQueue.invokeAndWait(new Runnable() {
            @Override public void run () {
                MyDialog d = new MyDialog();
                d.setVisible(true);
            }
        });
    }

    public static class MyDialog extends JDialog {
        private JLabel messageLbl;
        private JButton applyButton;


        public MyDialog () {
            super((Frame) null, true);
            setupGUI();

            applyButton.addActionListener(new ActionListener() {
                @Override
                public void actionPerformed (ActionEvent arg0) {
                    System.out.println("getPreferredSize()");
                    System.out.println("  " + getPreferredSize());
                    System.out.println("getLayout()");
                    System.out.println("  " + getLayout());
                    System.out.println("  " + getContentPane().getLayout());

                    pack();
                }
            });

            pack();
            setLocationRelativeTo(null);
        }

        private void setupGUI () {
            setResizable(true);
            Container panel = getContentPane();
            panel.setLayout(new MigLayout("debug, wrap 2", "[50%][50%]"));

            messageLbl = new JLabel("Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Sed posuere interdum sem. Quisque ligula eros ullamcorper quis, lacinia quis facilisis sed sapien.");
            panel.add(messageLbl, "width 700px!, center, span, wrap");

            panel.add(new JLabel("foo"));panel.add(new JLabel("bar"));

            applyButton = new JButton("apply...");
            panel.add(applyButton, "center, wrap, span");
        }
    }
}