A YouTube UI bug triggers an infinite layout reflow loop in the controls bar, pushing tabs past 7GB RAM and pinning CPU cores across Firefox, Brave, and Edge.
Key Takeaways
The bug lives in the flexible button container below the video player (Like, Dislike, Share); overflow detection and button hide/show cycle thousands of times per second.
Each cycle forces a full browser reflow: layout geometry recomputed, elements redrawn, rendering state updated – classic layout thrashing.
Affected browsers include both Firefox-based and Chromium-based engines, pointing to YouTube’s frontend as the origin, not a browser-specific regression.
Individual tabs have been reported consuming 7GB+ RAM with CPU cores near 100%; some users saw system-wide freezes.
Mozilla is investigating via Bugzilla; no confirmed fix yet and Google/YouTube have not publicly acknowledged the issue.
Hacker News Comment Review
One commenter notes BigQuery Studio triggers the same symptom on a fresh page load, suggesting Google has a broader pattern of shipping reflow-heavy UI across products.
