MigLayout: sizegroup based on smallest cell

Question

I would like to use the sizegroup keyword in miglayout to have 2 cells of the grid have the same width. The problem is that sizegroup stretches the shortest cell to reach the width of the longer, whereas i would want the opposite behaviour.

What i am trying to achieve is to have aTextField.width = btextField.width + bButton.width

import java.awt.Container;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextField;
import net.miginfocom.swing.MigLayout;


public class SizeGroupExample extends JFrame {
    
    private final MigLayout migLayout = new MigLayout("debug", "", "");
    private final JLabel aLabel = new JLabel("Label A");
    private final JTextField aTextField = new JTextField();
    private final JLabel bLabel = new JLabel("Label B");
    private final JTextField bTextField = new JTextField();
    private final JButton bButton = new JButton("Press");
    
    public SizeGroupExample() {
        Container container = getContentPane();
        container.setLayout(migLayout);
        add(aLabel, "");
        add(aTextField, "w 250!, sg 2, wrap");
        add(bLabel, "");
        add(bTextField, "split 2, sg 2");
        add(bButton, "wrap");
        setResizable(true);
        pack();
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLocationRelativeTo(null);
        setVisible(true);
    }
    
    public static void main(String[] args) {
        new SizeGroupExample();
    }
}

Answer 1

sizegroups are always aligned on the biggest component, so this won't work. But in the specific case described, you can get the expected result by growing the first field:

getContentPane().setLayout(new MigLayout("debug"));
add(new JLabel("Label A"), "");
add(new JTextField(), "growx, wrap");
add(new JLabel("Label B"), "");
add(new JTextField(), "width 200!, split 2, ");
add(new JButton("Press"), "wrap");
setResizable(true);
pack();
setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
setLocationRelativeTo(null);
setVisible(true);

This gives:

The total width is set by the second field and the button, and the first field expands to the width available.