The settings atom was a load-time snapshot with no storage listener and wrote the whole blob, so two tabs silently reverted each other. It now re-reads on storage events and writes only the keys that changed relative to the previous value. Unit-tested. Fixes #42 Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01PPmy3tPq869XDW4njjVaKA