How to display a dynamic List of JButtons in a JPanel

I have a panel that has a button above it to add a new category to a list and then I want to display that list below that button.

public class ConfigCategories extends JPanel {public final List<String> categories = new ArrayList<>();public ConfigCategories() {    super();    setLayout(new BoxLayout(this, BoxLayout.Y_AXIS));    setOpaque(false);    setBorder(BorderFactory.createTitledBorder(L10N.t("elementgui.config.categories.title")));    setMaximumSize(new Dimension(getPreferredSize().width, 50));    JButton addCategory = new JButton("Add New Category");    addCategory.setOpaque(false);    addCategory.setMaximumSize(new Dimension(Integer.MAX_VALUE, addCategory.getPreferredSize().height));    addCategory.setBackground(Theme.current().getBackgroundColor());    addCategory.setForeground(Theme.current().getForegroundColor());    addCategory.setMargin(new Insets(0, 0, 2, 0));    ComponentUtils.deriveFont(addCategory, 11);    addCategory.addActionListener(e -> {        new NewCategoryDialog(this);    });    add(addCategory);}public void update() {    for (String name: categories) {        JButton b = new JButton(name);        b.setMaximumSize(new Dimension(Integer.MAX_VALUE, b.getPreferredSize().height));        b.setBackground(Theme.current().getBackgroundColor());        b.setForeground(Theme.current().getForegroundColor());        b.setBorder(BorderFactory.createEmptyBorder());        add(b);    }    updateUI();}}

public class NewCategoryDialog extends JDialog {private final VTextField name = new VTextField(20);

public NewCategoryDialog(ConfigCategories configCategories) {    super(w, L10N.t("dialog.config.new_category"), true);    setSize(580, 195);    setLocationRelativeTo(w);    add(PanelUtils.westAndEastElement(L10N.label("Name:"), name));    JButton ok = new JButton(UIManager.getString("OptionPane.okButtonText"));    getRootPane().setDefaultButton(ok);    JButton cancel = new JButton(UIManager.getString("OptionPane.cancelButtonText"));    cancel.addActionListener(e -> setVisible(false));    ok.addActionListener(e -> {        setVisible(false);        configCategories.categories.add(name.getText());        configCategories.update();    });    add(BorderLayout.SOUTH, PanelUtils.join(ok, cancel));    setVisible(true);}}

This code works well, But I want to know how can I delete all the buttons added to the panel except the first button (button to add category)?

Because when I add the second, third, etc. button, the previous buttons are added again

Adding first button:

Adding second button: