How to show viewport on the docs page?

Describe the bug How to show viewport on the docs page? The canvas page has viewport options，But the documentation page is not。Is this a bug or does it require additional configuration?

Screenshots The canvas page has viewport options.

But the documentation page is not。

Code snippets

import { configure, addParameters } from '@storybook/react'
import { DocsPage, DocsContainer } from '@storybook/addon-docs/blocks'
import { INITIAL_VIEWPORTS } from '@storybook/addon-viewport'
import '../src/index.less'

addParameters({
    viewport: {
        viewports: INITIAL_VIEWPORTS
    },
    docs: {
        container: DocsContainer,
        page: DocsPage
    }
})