[docs] Fix scroll shift

[oliviertassinari]

The bug:

Enregistrement.de.l.ecran.2021-01-14.a.18.31.50.mp4

The origin: https://github.com/mui-org/material-ui/pull/15409/files#diff-e33c632b2237fb5233ca8600034cf02952cfaa668c9d6a5d08d5252891059d9dR59 @mbrookes Do you remember the issue this line was meant to fix?

Compare the loading UX between these two:

• HEAD: https://next.material-ui.com/components/alert/#variants
• PR: https://deploy-preview-24418--material-ui.netlify.app/components/alert/#variants

[mui-pr-bot]

No bundle size changes

Generated by 🚫 dangerJS against 5a67098

[eps1lon]

That scroll flipping is so annoying.

Though it seems like there is still some unstable scrolling:

1. Visit page
2. Scroll a bit
3. reload
   

Profiler filmstrip:

Profile: https://drive.google.com/file/d/1AMxC9PBf0may4TtrRHkU_uBSnA_ru8og/view?usp=sharing

[oliviertassinari]

Though it seems like there is still some unstable scrolling:

@eps1lon This is a different issue and only reproducible when there is a hash in the URL. I can observe the following: Next.js's reset the scroll with the scrollToHash() method, then, on the onload event, the browser restore the previous scroll position => double jump.

I have reported the bug in vercel/next.js#13653 (comment).

Thanks @dmtrKovalenko for reporting it in https://twitter.com/dmtrKovalenko/status/1348936828271910914. if we destructure your video there are 4 different issues bundled at once:

1. dark/light mode switch: Is using with Material UI or similar possible? pacocoursey/next-themes#2
2. the scrollIntoView issue of this PR that resets the scroll to the top position. Fixed ✅
3. The Next.js hash restore issue Scrolling happens when user returns to a page with hash using browser back button vercel/next.js#13653 (comment)
4. The date picker demo unstable rendering (the demo server-side is smaller than the demo client-side) https://next.material-ui.com/components/date-picker/#responsiveness

server

client

[eps1lon]

This is a different issue and only reproducible when there is a hash in the URL.

It's this exact issue that is still reproducible after scroll. So we did improve it, but not fully fix it.

[oliviertassinari]

I had a look at why the scroll into view was added. It's explained in #15409 (comment). I can't reproduce anymore