fix(content-preview): route compared-pane annotation scroll

[zhirongwang]

Summary

• Follow-up to fix(content-preview): keep compare open when clicking compared-pane annotation #4852. While comparing, a click on another version is sent to that pane (ref + handleAnnotationSelect) instead of switching this one.
• A current-version thread stays local so compare does not close. An other-version thread still notifies the host so the compared pane can follow.

Test plan

• Open a PDF with annotations on the current version and a previous version, then start side-by-side compare
• Click an annotation on the compared pane: compare stays open, that pane scrolls to the annotation
• Click a compared-version annotation in the activity sidebar: compared pane follows that version if needed and scrolls to it
• Click a current-version annotation in the sidebar: current pane scrolls, compared pane does not steal the scroll
• Click the same sidebar annotation twice: the preview pane still scrolls the second time
• Versions sidebar still changes the compared version as before

Summary by CodeRabbit

• Bug Fixes
  • In comparison view, selecting an annotation now directs scrolling to the pane showing that annotation’s version, rather than scrolling the wrong pane.
  • When the relevant preview is still loading, scrolling can wait until it is ready.
  • Selecting an annotation for the version already shown continues to scroll the current pane.

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• src/elements/content-preview/ContentPreview.js

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Walkthrough

ContentPreview routes annotation selections by file version during comparison. It scrolls to current-version annotations and forwards other-version annotations to the compared pane through a ref.

Changes

Comparison annotation routing

Layer / File(s)	Summary
Route annotation selections src/elements/content-preview/ContentPreview.js, src/elements/content-preview/__tests__/ContentPreview.test.js	ContentPreview scrolls to current-version annotations, including deferred scrolling, and forwards annotations for other versions. Tests cover scrolling, forwarding, and annotation-triggered host notifications.
Call the compared pane directly src/elements/content-preview/ContentPreview.js, src/elements/content-preview/__tests__/ContentPreview.test.js	The comparison wrapper uses a ref to call the compared pane’s handleAnnotationSelect method. The integration test checks that the defer flag is passed.

Priority: ⬇️ Low

Estimated code review effort: 2 (Simple) | ~15 minutes

Change: Bug fix

Sequence Diagram(s)

sequenceDiagram
  participant MainPreview
  participant ComparisonWrapper
  participant ComparedPreview
  MainPreview->>ComparisonWrapper: Forward annotation for another version
  ComparisonWrapper->>ComparedPreview: Call handleAnnotationSelect with deferScrollToOnload

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Suggested reviewers: ahorowitz123

Merge Risk: 🟡 Moderate · up to a801e

A cross-version selection from the Activity Sidebar may send the scroll request to the previous comparison pane, leaving the requested annotation unselected. Resolve or explicitly accept this gap before merging.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 1 functions across 2 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly identifies the main change: routing annotation scrolling to the compared pane in ContentPreview.
Description check	✅ Passed	The description includes a clear Summary and Test plan. It explains the comparison behavior, current-version and other-version annotation handling, and the intended validation steps. The repository te…
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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🔧 Biome (2.5.12)

src/elements/content-preview/ContentPreview.js

File contains syntax errors that prevent linting: Line 22: 'import type' are a TypeScript only feature. Convert your file to a TypeScript file or remove the syntax.; Line 37: 'import { type x ident }' are a TypeScript only feature. Convert your file to a TypeScript file or remove the syntax.; Line 69: 'import type' are a TypeScript only feature. Convert your file to a TypeScript file or remove the syntax.; Line 70: 'import type' are a TypeScript only feature. Convert your file to a TypeScript file or remove the syntax.; Line 71: 'import type' are a TypeScript only feature. Convert your file to a TypeScript file or remove the syntax.; Line 72: 'import type' are a TypeScript only feature. Convert your file to a TypeScript file or remove the syntax.; Line 73: 'import type' are a TypeScript only feature. Convert your file to a TypeScript file or remove the syntax.; Line 74: 'import type' are a TypeScript only feature. Convert your file to a TypeScript file or remove the syntax.; Line 75: '

... [truncated 18839 characters] ...

expected ) but instead found :; Line 1812: Expected a JSX attribute but instead found ')'.; Line 1810: Illegal return statement outside of a function; Line 1812: Unexpected token. Did you mean {'}'} or }?; Line 1812: Unexpected token. Did you mean {'>'} or >?; Line 1929: Expected a statement but instead found '}'.; Line 1932: 'export type' declarations are a TypeScript only feature. Convert your file to a TypeScript file or remove the syntax.; Line 1951: Type annotations are a TypeScript only feature. Convert your file to a TypeScript file or remove the syntax.; Line 1953: Expected an expression but instead found '?'.; Line 1953: expected : but instead found ;; Line 1954: Expected an expression but instead found '?'.; Line 1954: expected : but instead found ;

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_{A rabbit taps the preview pane,
Current notes scroll into view again.
Other versions cross the seam,
Deferred scrolls join the stream.
The compared pane receives the call,
And quiet carrots cheer them all.}

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Actionable comments posted: 2

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• 🪄 Fix CodeRabbit comments on this PR

🤖 Prompt to fix review comments

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only still-valid issues, skip the rest with a brief reason, keep changes
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Inline comments:
In `@src/elements/content-preview/ContentPreview.js`:
- Around line 648-650: Update handleAnnotationSelect so deferred annotation
requests are queued in dynamicOnPreviewLoadAction even when getViewer() returns
null. Preserve the existing immediate-selection behavior when a viewer is
available.
- Line 1658: Update the same-version branch around emitScrollToAnnotation in
ContentPreview so deferScrollToOnload registers dynamicOnPreviewLoadAction and
performs the appropriate frame or viewer scroll when the preview loads, then
clears the action. Keep immediate scrolling when deferral is false and preserve
the isOtherVersion path.

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• src/elements/content-preview/ContentPreview.js
• src/elements/content-preview/__tests__/ContentPreview.test.js

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