Bug: Focus restore after elements are reordered does not work in child windows

[hsin-2333]

demo of react-markdown
https://www.canva.com/design/DAGPlqdy1p0/RpTCf-mGQSFIP71O-Y8eWg/edit?utm_content=DAGPlqdy1p0&utm_campaign=designshare&utm_medium=link2&utm_source=sharebutton

react-markdown is a markdown component for React.

👉 Changes are re-rendered as you type.

👈 Try writing some markdown on the left.

Overview

• Follows CommonMark
• Optionally follows GitHub Flavored Markdown
• Renders actual React elements instead of using dangerouslySetInnerHTML
• Lets you define your own components (to render MyHeading instead of 'h1')
• Has a lot of plugins

Contents

[JuneLin2001]

[rebeccaS47]

built an app to get reviews for this PR
https://www.n0va-io.com/discover/facebook/react

[rebeccaS47]

Repro steps
Initialize useRef with some dummy value (e.g. null, Symbol, undefined, etc.) to be changed after initialization/during render.
Update ref.current by checking whether it is equivalent to its initial condition (as per documentation: useRef#Avoiding recreating the ref contents)
To solve it, you may initialize the ref like this instead:

[hsin-2333]

print('helo')

[hsin-2333]

hello there

[hsin-2333]

A demo of react-markdown

react-markdown is a markdown component for React.

👉 Changes are re-rendered as you type.

👈 Try writing some markdown on the left.

Overview

• Follows CommonMark
• Optionally follows GitHub Flavored Markdown
• Renders actual React elements instead of using dangerouslySetInnerHTML
• Lets you define your own components (to render MyHeading instead of 'h1')
• Has a lot of plugins

[JuneLin2001]

1. Initialize useRef with some dummy value (e.g. null, Symbol, undefined, etc.) to be changed after initialization/during render.
2. eslint-plugin-react-compiler gives error

function Video() {
  const playerRef = useRef(null);
  if (playerRef.current === null) {
    playerRef.current = new VideoPlayer();
  }
  // ...

[JuneLin2001]