Scroll wheel use freezes screen

[peterlandry]

What happened?

I suspect scroll events from a scroll wheel aren't being debounced properly. If I'm viewing diffs (with or without --watch), doing a large quick scroll freezes the UI. There are some partial torn redraws that happen, then eventually it settles.

Steps to reproduce

Open a diff that requires scrolling. Do a large scroll by "flicking" the scroll wheel.

Expected behavior

Scrolling to happen, and stop at the top or bottom.

Version

0.17.1

[benvinegar]

I took a look and came up empty; I can't reproduce. Can you give me more information? e.g.

1. OS/architecture, terminal/version, tmux/SSH, etc
2. Wrap/layout/theme configuration and whether agent notes are present
3. Approximate file count and changed-line count
4. A shareable patch or synthetic reproduction
5. A short screen recording.

[peterlandry]

1. MacOS / ghostty build 16124 / herdr
2. No agent notes, default theme
3. Seems to happen with any counts. I think last instance was 3 or 4 changed files, a few hundred lines of code change
4. TODO
5. TODO

[zivattias]

I can also confirm this behavior, using Ghostty + Herdr.

EDIT: Only when using hunk diff --watch

[benvinegar]

So, I've seen my colleague @tridha643 experience this with herdr (I was sitting over his shouler). So that's 3 people experiencing this with herdr.

His agents were maxing out the CPU on his machine (100% utilization). What does your system utilization look like when this happens?

[benvinegar]

And what version of hunk btw? Are you using 0.17.3?

[kazu728]

CleanShot.2026-07-24.at.04.35.42.mp4

❯ hunk --version
0.17.3

❯ bun --version
1.3.13

Same issue here. I'm not sure which language triggered the original report, but for Japanese text specifically, I suspect the bottleneck might not be Herdr's own overhead — it could be the regex, which is fairly expensive and may be getting invoked on every scroll event, possibly causing the lag.

[benvinegar]

We think the fix is in this release: https://github.com/modem-dev/hunk/releases/tag/v0.17.4

Give it a shot?

which is fairly expensive and may be getting invoked on every scroll event, possibly causing the lag.

Yep, probably

[benvinegar]

@kazu728 Did you want to submit that commit as a PR?

[kazu728]

@benvinegar

CleanShot.2026-07-25.at.01.30.10.mp4

I feel it's better now. It still has a bit of lag, but it's practical enough, thank you.

Did you want to submit that commit as a PR?

Either is fine for me, as long as this issue gets fixed. I've attached a recording to the PR, but feel free to handle it however's easiest for you to maintain.