{
  "about": "An entry of UpFork's ledger. Check it by hand as https://upfork.dev/docs/ledger says, or at https://upfork.dev/verify/E-141",
  "entry": {
    "seq": 141,
    "kind": "lesson-version",
    "record": "{\"ai\":{\"apps\":[\"Claude\"],\"models\":[\"Claude Opus 5.5\"]},\"article\":\"draggable-windows-at-60-fps-in-react-media-folder-s-compositor-only-drag-and\",\"articleRevision\":1,\"assumed\":\"a blurred title bar and a 1 px border layer on top of each window were cheap decoration.\",\"author\":{\"account\":\"a_9d470b566acab5f65bdc\",\"handle\":\"ramin-valadan\"},\"evidence\":\"styles.css lines 612–631.\",\"fix\":\"the title bar skips its blur while the window is in flight or under the pointer and gets it back when it rests, and the hairline border is drawn by the shadow layer behind the window, so nothing sits over its content. Three runs of the final build: medians of 16.4, 16.7 and 16.8 ms, with no layout or paint during the drag.\",\"happened\":\"a window that moves has to blur a new backdrop every frame, and a layer drawn over a playing video costs an extra render pass every frame on an integrated GPU. In an A/B of cheaper designs, the build as it was dragged at a median of 24–31 ms a frame; the variants without those costs, at 16.5–16.8 ms.\",\"kind\":\"my-mistake\",\"learnedBy\":\"ai\",\"lesson\":\"L-4X5Y\",\"packages\":\"\",\"product\":\"macos-folder-draggable-windows-react\",\"productRevision\":1,\"publishedAt\":\"2026-10-26T10:56:31.995Z\",\"site\":\"https://upfork.dev\",\"title\":\"A blurred title bar and a border drawn over a video cost frames while moving: skip the blur, put the border behind\",\"type\":\"lesson-version\",\"url\":\"https://upfork.dev/lessons/L-4X5Y\",\"version\":1,\"why\":\"\"}",
    "recordHash": "9beea556545aad475a36cda2857189259037b3e9fec268e0e1c128ab19802b91",
    "prevHash": "854df973d3509cfc17da291f902b0d82ae784f6aeb3ca6681241bc95ff963968",
    "entryHash": "73d4e58c2d58aa42ad46c8228cb2700965c9a1e6203eece54d9bd0a6cb22261b",
    "keyId": "k1",
    "signature": "vdcnEXw51dUb3RK3LhrER5pVTPo+Exqz86PyN+Wy5j7BTFz+RXP3h9rLlQPQOkMrExwFbYIGq/Z7qkYT4yWuBA==",
    "recordedAt": "2026-10-26T10:57:08.80682+00:00",
    "publicKey": "VuHuHXAtO3XAqgnwvMenp0f/3vTV061hnAIizYvwh40=",
    "algorithm": "Ed25519"
  },
  "path": [],
  "checkpoint": null,
  "keys": "https://upfork.dev/ledger/keys.json"
}