```js
// .storybook/my-addon/register.js

addons.register(ADDON_ID, () => {
  addons.add(PANEL_ID, {
    type: types.PANEL,
    title: 'My Addon',
    render: () => <div>Addon tab content</div>,
    paramKey: 'myAddon', // this element
  });
});
```