In a handful of places, we're using effect(...) to defer work that only needs to happen once (like autofocusing an element). This is overkill. There is a much cheaper and simpler way that already exists in the codebase — queue_micro_task.
It feels like we could probably use it in more places, but when I tried it causes some tests to fail, likely because of subtle timing issues that don't apply to the things changed in this PR.
Rich Harris