## Summary
When using React DevTools to highlight component updates, the highlights
would sometimes appear behind elements that use the browser's
[top-layer](https://developer.mozilla.org/en-US/docs/Glossary/Top_layer)
(such as `<dialog>` elements or components using the Popover API). This
made it difficult to see which components were updating when they were
inside or behind top-layer elements.
This PR fixes the issue by using the Popover API to ensure that
highlighting appears on top of all content, including elements in the
top-layer. The implementation maintains backward compatibility with
browsers that don't support the Popover API.
## How did you test this change?
I tested this change in the following ways:
1. Manually tested in Chrome (which supports the Popover API) with:
- Created a test application with React components inside `<dialog>`
elements and custom elements using the Popover API
- Verified that component highlighting appears above these elements when
they update
- Confirmed that highlighting displays correctly for nested components
within top-layer elements
2. Verified backward compatibility:
- Tested in browsers without Popover API support to ensure fallback
behavior works correctly
- Confirmed that no errors occur and highlighting still functions as
before
3. Ran the React DevTools test suite:
- All tests pass successfully
- No regressions were introduced
[demo-page](https://devtools-toplayer-demo.vercel.app/)
[demo-repo](https://github.com/yongsk0066/devtools-toplayer-demo)
### AS-IS
https://github.com/user-attachments/assets/dc2e1281-969f-4f61-82c3-480153916969
### TO-BE
https://github.com/user-attachments/assets/dd52ce35-816c-42f0-819b-0d5d0a8a21e5
YongSeok Jang (장용석)