Java MigLayout非法约束“dock”

我正在尝试创建一个按钮并使用布局管理器将按钮停靠到面板的右侧,但出现以下错误:

线程“main”java.lang.IllegalArgumentException中出现异常:非法 约束:“dock”未知关键字。

package testpackage;

import java.awt.Dimension;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;

import net.miginfocom.swing.MigLayout;

public class MigPanel {
    JFrame frame = new JFrame();
    JPanel panel = new JPanel();
    MigLayout migLayout = new MigLayout();
    Dimension panelDimension = new Dimension(500,500);
    Dimension frameDimension = new Dimension(1000,1000);

    JButton submitButton = new JButton();
    Dimension buttonDimension = new Dimension(30,30);

    JButton submitButton2 = new JButton();
    Dimension buttonDimension2 = new Dimension(30,30);
    public MigPanel() {
        this.createLayout();
        this.createButton();
    }
    private void createLayout() {
        this.frame.add(this.panel);
        this.frame.setMinimumSize(frameDimension);
        this.frame.setVisible(true);

        this.panel.setLayout(migLayout);
        this.panel.setMinimumSize(panelDimension);
        this.panel.setVisible(true);
    }
    public void createButton() {
        this.submitButton.setSize(buttonDimension);
        this.submitButton.setVisible(true);
        this.panel.add(submitButton, "dock right");
    }
    public void setPanelVisible() {
        this.panel.setVisible(true);
    }

    public static void main(String[] args) {
        MigPanel migPanel = new MigPanel();
    }
}