renderDetails() revealed the card inside render(), whose preserveScroll() wrapper restored the previous scrollTop in its finally block, undoing the reveal. The reveal now runs in the DETAILS open handler after render() returns, once per opening; closing and refreshes do not scroll.
Clears the timeout guards once each race settles, measures the 15,000-vehicle transit ingestion with main-thread CPU time instead of wall time, and times the region-timeout case from the boundary lookup with a 2 s ceiling, below the 3 s default budget, so an ignored budget still fails.
Co-authored-by: Sameh Khamis <[email protected]>
Ian Blenke