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Test Info: Warnings

<!DOCTYPE html>
<title>Layout Instability: ignore fixed and sticky positioning</title>
<link rel="help" href="" />
body { height: 2000px; }
#f1, #f2 {
position: fixed;
width: 300px;
height: 100px;
left: 100px;
background: yellow;
#f1 { top: 0; }
#f2 { top: 150px; will-change: transform; }
#s1 {
position: sticky;
width: 200px;
height: 100px;
left: 450px;
top: 0;
background: blue;
<div id='f1'>fixed</div>
<div id='f2'>fixed composited</div>
<div id='s1'>sticky</div>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="resources/util.js"></script>
promise_test(async () => {
const watcher = new ScoreWatcher;
// Wait for the initial render to complete.
await waitForAnimationFrames(2);
// Scroll down by 50px.
document.scrollingElement.scrollTop = 50;
// Force a layout. = "2500px";
// No layout shift should occur as a result of the scroll-triggered
// repositioning of fixed and sticky elements.
await waitForAnimationFrames(3);
assert_equals(watcher.score, 0);
}, 'Ignore fixed and sticky.');