Worked on the facebook/react repository to enhance the React DevTools user experience by stabilizing overlay highlight behavior in the Components inspector. Developed a feature using JavaScript and React that introduced a native mouseleave event listener, ensuring highlight overlays are cleared immediately when the cursor exits the DevTools panel. Addressed cross-origin and browser extension compatibility by leveraging the ownerDocument property, which improved reliability across different environments. The implementation was validated through both manual end-to-end testing and the ReactDevTools automated test suite. This work resulted in a smoother debugging workflow by preventing stale highlights and enabling faster, more accurate issue diagnosis.