What is CLS by scroll behavior
CLS by scroll behavior shows how Cumulative Layout Shift (CLS) varies based on the scroll state of the page:
Non-scrollable: The page doesn’t require scrolling
Scrollable: The page has scrollable content, but wasn’t actively scrolled
Scrolled: The user returned to the page and the browser restored their previous scroll position
This lens helps you spot layout instability introduced when restoring scroll positions — a common issue in SPAs and back-forward navigations.
Healthy CLS by scroll behavior sample
A healthy scroll behavior lens looks like this:
All three scroll states show low CLS
Restoring scroll positions doesn’t cause layout jumps
Dynamic or long pages still remain visually stable when re-entered
This signals that your content, ads, fonts, and late-loading elements are handled gracefully — regardless of where the user lands.
Unhealthy CLS by scroll behavior sample
Common symptoms of an unhealthy pattern:
Higher CLS on Scrolled views — indicating layout jumps during back/forward navigations
Late-rendered content (e.g. banners, sticky headers, or injected ads) appearing after scroll is restored
Non-scrollable pages with CLS issues may indicate instability even on simple views — often caused by fonts, carousels, or DOM reordering
These shifts can confuse returning users, break their flow, or reduce trust on important transactional pages.
Resolving unhealthy CLS by scroll behavior
Go-to action plan to resolve an unhealthy CLS by scroll behavior:
Ask Uxi to analyze your CLS by scroll behavior values and suggest improvements
Use Filters to isolate high-CLS scroll types, then cross-check against devices, route types, or async content loading.
Simulate CLS of the suspected lens to see if fixing it will resolve the CLS by scroll behavior. If yes, this is where the resolution focus should be.
Use an automated CLS optimization tool like Navigation AI to improve your CLS by scroll behavior values
Once you’ve improved CLS, set an alert to be the first to know if it starts worsening again.
Try it yourself
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