fix(web): preserve virtualized diff scrolling

[Khrisseh1995]

Fixes #4525

What Changed

Conditionally apply the existing top: 0 and bottom: auto overrides when all diff files are collapsed.

Why

Commit 38cfc25 made the override unconditional. This prevents the virtualizer from positioning expanded diff content and causes scrolling to drift.

Removing the override entirely restores a gap above the all-collapsed file list, so keeping it conditional preserves both behaviours.

UI Changes

Before: expanded diffs drift behind the scrollbar as files are traversed.

After: expanded diffs follow the virtualizer while collapsed file headers remain aligned below the toolbar.

Collapsed Spacing Video:

collapsed-spacing-before-after.mp4

Virtual Scroll Video:

virtual-scroll-varied-lengths.mp4

Checklist

• This PR is small and focused
• I explained what changed and why
• I included before/after screenshots for any UI changes (N/A: interaction-only; see videos)

---

Note

Low Risk
Single conditional class change in DiffPanel UI styling with no auth, data, or API impact.

Overview
Fixes virtualized diff scrolling in the diff panel by only applying the virtualizer top/bottom CSS overrides when all diff files are collapsed.

AnnotatableCodeView previously always included [&>div>div:last-child]:top-0! and bottom-auto!, which broke the virtualizer’s positioning for expanded files and caused scroll drift. Those classes are now added via cn() only when allDiffFilesCollapsed is true, so expanded diffs scroll correctly while the all-collapsed header layout stays aligned.

^{Reviewed by Cursor Bugbot for commit b71f197. Bugbot is set up for automated code reviews on this repo. Configure here.}

Note

Fix diff render surface scroll position in non-collapsed state

The CSS overrides top:0 and bottom:auto on the last child of AnnotatableCodeView in DiffPanel.tsx were always applied, breaking scroll behavior when diff files are expanded. They are now conditional on allDiffFilesCollapsed, restoring correct virtualized scroll positioning in the non-collapsed state.

^{Macroscope summarized b71f197.}

[coderabbitai]

Important

Review skipped

Auto reviews are disabled on this repository. Please check the settings in the CodeRabbit UI or the .coderabbit.yaml file in this repository. To trigger a single review, invoke the @coderabbitai review command.

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro Plus

Run ID: ef0c2098-6e5f-408d-96a9-491cc0d10514

You can disable this status message by setting the reviews.review_status to false in the CodeRabbit configuration file.

Use the checkbox below for a quick retry:

• 🔍 Trigger review

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}

[macroscopeapp]

Approvability

Verdict: Approved

Minor CSS fix that conditionally applies styling for virtualized diff scrolling. The change is self-contained to a className prop and only affects visual behavior when all diff files are collapsed.

^{You can customize Macroscope's approvability policy. Learn more.}