- Cache the UMD/game cover templates AND their transparent-window rects (computed once, under a lock). The old code re-ran an O(w*h) Python pixel scan on every composited cover, stalling video cover loading and scraping for ~1s per cover with GIL contention. - ScrapeDialog: ignore stale search/scrape results via a generation counter and cancel in-flight workers when a new search/scrape starts; clear threads on close. - MetadataWorker (library details): cancel stale metadata fetches and delete finished workers/threads instead of leaking one per item selection.