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 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