# Lenis smooth scroll with Astro's ClientRouter > A navigation made while Lenis is still easing scrolls the next page to the old page's target. lenisPage stops the animation and resyncs Lenis after every ClientRouter swap. ## The symptoms These apply only to sites that use ``. We measured them with Lenis 1.3.26 on Astro 7.3.2 in Chromium and Firefox. - **The next page opens part-way down.** Click a link, or press back, while Lenis is still easing from a wheel scroll, and the animation keeps running after the router has scrolled the new page. A navigation 120 ms into a 1200 px wheel scroll left the next page at 1200 px instead of the top. A 2023 report describes a next page that does not start at the top ([withastro/astro#7758](https://github.com/withastro/astro/issues/7758)). - **Instances pile up.** Creating Lenis inside an `astro:page-load` listener adds an instance, with its own animation frame loop, on every navigation unless you call `destroy()`: three instances after two navigations. When Lenis is at rest during a navigation, it follows the router by itself: the next page starts at the top, and the back button restores the old position. Reports from 2024 also show Firefox logging "Too many calls to Location or History APIs within a short timeframe", because the router saved the scroll position on every `scrollend` event and Lenis' scrolling fired one after every scroll event ([withastro/astro#12725](https://github.com/withastro/astro/issues/12725), [darkroomengineering/lenis#348](https://github.com/darkroomengineering/lenis/issues/348)). We could not reproduce it with Lenis 1.3.26 and Astro 7.3.2: ten wheel ticks made one `history.replaceState` call. ## Why it happens `` keeps the document and swaps its contents, then scrolls the window to the top or to the position it restores. Lenis keeps its own target and animation across the swap. While an animation runs, Lenis ignores native scroll events and keeps writing its own position, so the new page ends up where the old page's scroll was heading. Lenis 1.3.26 has a `stopInertiaOnNavigate` option for this, off by default. It reacts to clicks on links, and in our test the back button still carried the animation over. ## The fix Create Lenis once for the life of the document, and stop and resync it after every swap. `lenisPage` does that: ```ts // src/layouts/Base.astro — inside