Scroll lag / stutter when page zoom is exactly 100%

Describe the bug

🐛 Bug: Scroll lag / stutter when page zoom is exactly 100%

Description

When using @tanstack/virtual, scrolling becomes noticeably laggy/stuttery if the browser page zoom is set to 100% (default).
Interestingly, the issue disappears and scrolling becomes smooth again when changing the page zoom to 90% or 110%.

This behavior is consistently reproducible and seems to be tied specifically to the 100% zoom level.

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🔁 Steps to Reproduce

1. Open an app/page that uses @tanstack/virtual
2. Set browser zoom to 100%
3. Scroll the virtualized list
   → Observe scroll lag / stuttering
4. Change browser zoom to 90% or 110%
5. Scroll again
   → Scrolling becomes smooth

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✅ Expected Behavior

Scrolling should be smooth and consistent regardless of browser zoom level (including the default 100%).

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❌ Actual Behavior

Scrolling is laggy only when zoom is exactly 100%.
Non-100% zoom levels do not show the issue.

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🧠 Additional Notes / Observations

• This may be related to:

  • sub-pixel rounding
  • layout measurements using fractional values
  • getBoundingClientRect, offsetHeight, or ResizeObserver behavior at 100% zoom

• The issue occurs even on high-performance machines

• The problem feels like repeated re-layout or recalculation during scroll

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🧪 Environment

• Library: @tanstack/virtual
• Browser: (Chrome / Edge / Firefox / Brave)
• OS: (Windows)
• tanstack/virtual version: 3.13.5

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📎 Reproduction

Please clone the repository and run Storybook to reproduce the issue.
http://localhost:6006/?path=/story/components-datagrid--default

Repository:
https://github.com/quanghiep03198/FE-WMS

The issue can be observed directly in Storybook and is isolated to the usage of @tanstack/virtual.

Your minimal, reproducible example

http://localhost:6006/?path=/story/components-datagrid--default

Steps to reproduce

Scrolling should be smooth and consistent regardless of browser zoom level (including the default 100%).

Expected behavior

When using @tanstack/virtual, scrolling becomes noticeably laggy/stuttery if the browser page zoom is set to 100% (default).
Interestingly, the issue disappears and scrolling becomes smooth again when changing the page zoom to 90% or 110%.

This behavior is consistently reproducible and seems to be tied specifically to the 100% zoom level.

How often does this bug happen?

Every time

Screenshots or Videos

https://www.loom.com/share/8fedb0086ade42d5855986d2951c856d

Platform

• OS: Windows
• Browsers: Chrome/Edge/Brave

tanstack-virtual version

3.13.5

TypeScript version

5.7.3

Additional context

When using default page zoom (100%)

Terms & Code of Conduct

• I agree to follow this project's Code of Conduct
• I understand that if my bug cannot be reliable reproduced in a debuggable environment, it will probably not be fixed and this issue may even be closed.

Start with the linked Storybook reproduction in the FE-WMS repository and compare scrolling at 100% against 90% and 110% browser zoom using @tanstack/virtual 3.13.5. Investigate the reported measurement and layout behavior around the virtualized list, then verify that scrolling is smooth and consistent at all three zoom levels.