SSCCE JList + JScrollPane scrolling to bottom.

//YOU NEED TO MANUALLY ADD A "package ...;" HERE.


import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.BoxLayout;
import javax.swing.DefaultListModel;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollBar;
import javax.swing.JScrollPane;
import javax.swing.JSeparator;
import javax.swing.ListSelectionModel;
import javax.swing.SwingConstants;

public class Foo extends JPanel implements ActionListener {
    private DefaultListModel<String> model;
    private JList<String> triggerList;
    private JScrollPane scrollPane;
    private JButton createButton;
    private JButton removeButton;

    public Foo() {
        super();
        this.setLayout(new BoxLayout(this, BoxLayout.PAGE_AXIS));
        constructingList();
        constructingButtons();
    }

    private void constructingButtons() {
        JPanel panel = new JPanel();
        Dimension size = new Dimension(90, 20);

        this.createButton = new JButton("Create");
        this.createButton.setActionCommand(Integer.toString(0));
        this.createButton.addActionListener(this);
        this.createButton.setSize(size);
        this.createButton.setMaximumSize(size);
        this.createButton.setMinimumSize(size);
        this.createButton.setPreferredSize(size);
        panel.add(createButton);

        panel.add(new JSeparator(SwingConstants.HORIZONTAL));

        this.removeButton = new JButton("Remove");
        this.removeButton.setActionCommand(Integer.toString(1));
        this.removeButton.addActionListener(this);
        this.removeButton.setSize(size);
        this.removeButton.setMaximumSize(size);
        this.removeButton.setMinimumSize(size);
        this.removeButton.setPreferredSize(size);
        panel.add(removeButton);

        this.add(panel);
    }

    private void constructingList() {
        this.model = new DefaultListModel<String>();
        this.triggerList = new JList<String>();
        this.triggerList.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
        this.triggerList.setLayoutOrientation(JList.VERTICAL);
        this.triggerList.setVisibleRowCount(0);

        // I don't know how to provide dynamic height here. It's always fixed.
        Dimension size = new Dimension(200, 300);
        this.triggerList.setSize(size);
        this.triggerList.setMinimumSize(size);

        this.triggerList.setModel(this.model);
        scrollPane = new JScrollPane(this.triggerList);
        size = new Dimension(200, 300);
        scrollPane.setPreferredSize(size);
        scrollPane.setSize(size);

        scrollPane.setVisible(true);
        this.add(scrollPane);
    }

    @Override
    public void actionPerformed(ActionEvent event) {
        switch (Integer.valueOf(event.getActionCommand())) {
            default:
                break;
            case 0: {// Create Button
                System.out.println("CREATE");
                short value = Short.valueOf((short) (this.model.getSize() & Short.MAX_VALUE));
                this.model.addElement("<Untitled> " + Short.toString(value));
                this.validate();
                JScrollBar vertical = scrollPane.getVerticalScrollBar();
                vertical.setValue(vertical.getMaximum() + 1);
                break;
            }
            case 1: {// Remove button
                System.out.println("REMOVE");
                int index = this.triggerList.getSelectedIndex();
                if (index != -1)
                    this.model.remove(index);
                else if (!this.model.isEmpty())
                    this.model.remove(this.model.getSize() - 1);

                break;
            }
        }
        this.triggerList.validate();
    }

    public static void main(String[] args) {
        JFrame frame = new JFrame("Script Hobby (Hobby)");
        frame.add(new Foo());
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setVisible(true);
    }
}