// Replace this with a relevant selector. // If you use a tool that auto-generates classes, // you can temporarily add an ID and select it // with '#id'. const selector = '.the-fixed-child'; function findCulprits(elem) { if (!elem) { throw new Error( 'Could not find element with that selector' ); } let parent = elem.parentElement; while (parent) { const { transform, willChange } = getComputedStyle(parent); if (transform !== 'none' || willChange === 'transform') { console.warn( '🚨 Found a culprit! 🚨\n', parent, { transform, willChange } ); } parent = parent.parentElement; } } findCulprits(document.querySelector(selector));