Popover popup flickers when scrolling page, parent has sticky position

[Dannymx]

Bug report

Current behavior

I wanted to replicate shadcn's website navigation for mobile view but I realized after using Base UI's popover it started to flicker every time I scrolled the page.

Expected behavior

• Not to flicker when scrolling on a page

Reproducible example

StackBlitz

And the preview:
https://tsckkqdxrun-zp2n--5173--365214aa.local-credentialless.webcontainer.io/media

Enable the Chrome mobile view to see the flickering.

Video example of the issue:

CleanShot.2025-12-31.at.16.00.44.mp4

Also reproducible on iOS 26 with Safari:

ScreenRecording_12-31-2025.16-08-37_1-cropped.mov

Base UI version

"@base-ui/react": "1.0.0",

Which browser are you using?

Chrome Version 143.0.7499.110 (Official Build) (arm64)

Which OS are you using?

Mac OS 26

Which assistive tech are you using (if applicable)?

N/A

Additional context

None

[atomiks]

The positionMethod prop prevents the flickering here:

<Popover.Positioner positionMethod="fixed">

The Radix popover defaults to this ("fixed") behavior, which works nice in this kind of sticky scenario, but is worse in typical scenarios compared to absolute which is why we didn't default to that.

[LukasTy]

The suggested fix solves the problem.
After all, I think that in the example's case, page scrolling should be locked when the menu is open. 🤷
@Dannymx, is there anything else to address here?

[Dannymx]

Suggested fix above fixes this, closing this issue.