fix: prevent scroll jump when closing thread in narrow layout

[sidd19898]

Fix for #41132

 ### Problem
 In narrow/responsive layout, closing a thread panel causes the main chat to jump back many messages instead of 
 staying at the same scroll position.

 ### Root Cause
 In narrow layout, the contextual bar aside was a flex child that took 100% width, squeezing the main chat body 
 to 0 width. When the thread closed and the aside unmounted, the body expanded back, causing the VList 
 virtualizer to re-measure and reset scroll position to top.
                                                                                                                  
 ### Fix                                                                                                          
 1. **RoomLayout.tsx**: Wrap the aside in an absolutely positioned `Box` when `contextualbarPosition ===          
 'absolute'` (narrow mode), so it overlays the body instead of affecting its flex layout.
 2. **ContextualbarDialog.tsx**: Remove `restoreFocus` from `FocusScope` to prevent unwanted focus restoration  
 when closing the contextual bar.
                                                                                                                  
 ### Testing
 1. Open Rocket.Chat in a narrow browser window (< 780px)
 2. Open a channel and scroll to a message in the middle                                                          
 3. Click "View thread" on a message
 4. Close the thread
 5. Verify the main chat maintains its scroll position

Summary by CodeRabbit

• Bug Fixes
  • Improved responsive layout behavior for the side panel, ensuring it stays properly positioned and sized on smaller and larger screens.
  • Fixed breakpoint handling so responsive states are applied more reliably when size information is unavailable.

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Reviewing files that changed from the base of the PR and between 16bcf67 and c450fce.

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• apps/meteor/client/views/room/layout/RoomLayout.tsx

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• apps/meteor/client/views/room/layout/RoomLayout.tsx

🧠 Learnings (2)

📚 Learning: 2026-03-27T14:52:56.865Z

Learnt from: dougfabris
Repo: RocketChat/Rocket.Chat PR: 39892
File: apps/meteor/client/views/room/contextualBar/Threads/Thread.tsx:150-155
Timestamp: 2026-03-27T14:52:56.865Z
Learning: In Rocket.Chat, there are two different `ModalBackdrop` components with different prop APIs. During review, confirm the import source: (1) `rocket.chat/fuselage` `ModalBackdrop` uses `ModalBackdropProps` based on `BoxProps` (so it supports `onClick` and other Box/DOM props) and does not have an `onDismiss` prop; (2) `rocket.chat/ui-client` `ModalBackdrop` uses a narrower props interface like `{ children?: ReactNode; onDismiss?: () => void }` and handles Escape keypress and outside mouse-up, and it does not forward arbitrary DOM props such as `onClick`. Flag mismatched props (e.g., `onDismiss` passed to the fuselage component or `onClick` passed to the ui-client component) and ensure the usage matches the correct component being imported.

Applied to files:

• apps/meteor/client/views/room/layout/RoomLayout.tsx

📚 Learning: 2026-05-06T12:21:44.083Z

Learnt from: juliajforesti
Repo: RocketChat/Rocket.Chat PR: 40256
File: apps/meteor/client/components/CreateDiscussion/CreateDiscussion.tsx:121-149
Timestamp: 2026-05-06T12:21:44.083Z
Learning: Field wrappers in rocket.chat/fuselage-forms (Field, FieldLabel, FieldRow, FieldError, FieldHint) auto-create htmlFor/id associations, aria-describedby, and role="alert" for errors. Do not manually set htmlFor, id, aria-describedby, or role attributes when using these wrappers. This automatic wiring does not apply to plain rocket.chat/fuselage components, which require explicit ID wiring per the accessibility docs. In code reviews, prefer using fuselage-forms wrappers for form fields and verify there is no unnecessary manual ID/aria wiring in files that use these wrappers. If a component uses plain fuselage components, ensure proper id wiring as per docs.

Applied to files:

• apps/meteor/client/views/room/layout/RoomLayout.tsx

🔇 Additional comments (1)

apps/meteor/client/views/room/layout/RoomLayout.tsx (1)

26-26: 🎯 Functional Correctness

No change needed here. The !borderBoxSize.inlineSize fallback matches the existing breakpoint-helper pattern and keeps the contextual bar in the wide state until the first measurement.

			> Likely an incorrect or invalid review comment.

---

Walkthrough

RoomLayout's breakpoint filter now allows breakpoints with minViewportWidth to match even when borderBoxSize.inlineSize is undefined. The aside content rendering is updated to conditionally wrap content in an absolutely positioned Box (right-aligned, sized by contextualbarSize) when contextualbarPosition is 'absolute', otherwise rendering directly, both within Suspense.

Changes

Contextualbar layout updates

Layer / File(s)	Summary
Breakpoint filter and responsive aside positioning apps/meteor/client/views/room/layout/RoomLayout.tsx	Breakpoint filter predicate updated to match minViewportWidth breakpoints when inlineSize is unavailable; aside content conditionally wrapped in an absolutely positioned, right-aligned Box sized by contextualbarSize when contextualbarPosition is 'absolute', within Suspense.

Estimated code review effort: 2 (Simple) | ~10 minutes

Possibly related PRs

• RocketChat/Rocket.Chat#40757: Both PRs modify RoomLayout.tsx's contextual bar/aside layout logic keyed off contextualbarSize and its positioning.

Suggested labels: type: bug

Suggested reviewers: cardoso, tassoevan

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly matches the main fix: preventing scroll jumps in narrow layout when closing the thread panel.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
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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[coderabbitai]

Actionable comments posted: 1

🧹 Nitpick comments (1)

apps/meteor/client/views/room/layout/RoomLayout.tsx (1)

68-78: 📐 Maintainability & Code Quality | 🔵 Trivial | 💤 Low value

LGTM overall; consider a named z-index token instead of a magic number.

The absolute-positioning wrap correctly isolates the aside from flex layout so the body no longer collapses/re-expands on mount/unmount, addressing the root cause described in the PR. Minor nit: zIndex={100} is a hardcoded value — consider defining it as a constant or using fuselage's z-index tokens if available, for consistency with other overlay layers in the app.

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@apps/meteor/client/views/room/layout/RoomLayout.tsx` around lines 68 - 78,
The absolute-positioned aside in RoomLayout correctly fixes the layout issue,
but the hardcoded zIndex value should be replaced with a named token or shared
constant for consistency. Update the Box wrapper in RoomLayout to use an
existing fuselage z-index token or define a local constant for this overlay
layer, so the layering is easier to maintain alongside other components using
contextualbarPosition and aside.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@packages/ui-client/src/components/Contextualbar/ContextualbarDialog.tsx`:
- Line 41: The FocusScope in ContextualbarDialog should keep focus restoration
when the contextual bar closes; adding only autoFocus is not enough. Update the
FocusScope usage in ContextualbarDialog to restore focus to the trigger on
close, and if scroll jumping is the concern, preserve restoreFocus while using
preventScroll rather than removing restoration behavior.

---

Nitpick comments:
In `@apps/meteor/client/views/room/layout/RoomLayout.tsx`:
- Around line 68-78: The absolute-positioned aside in RoomLayout correctly fixes
the layout issue, but the hardcoded zIndex value should be replaced with a named
token or shared constant for consistency. Update the Box wrapper in RoomLayout
to use an existing fuselage z-index token or define a local constant for this
overlay layer, so the layering is easier to maintain alongside other components
using contextualbarPosition and aside.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 51c1c9d0-e3f6-422c-a456-b932395ca77b

📥 Commits

Reviewing files that changed from the base of the PR and between 1cc7bbd and 16bcf67.

📒 Files selected for processing (2)

• apps/meteor/client/views/room/layout/RoomLayout.tsx
• packages/ui-client/src/components/Contextualbar/ContextualbarDialog.tsx

📜 Review details

⏰ Context from checks skipped due to timeout. (1)

• GitHub Check: cubic · AI code reviewer

🧰 Additional context used

📓 Path-based instructions (1)

**/*.{ts,tsx,js}

📄 CodeRabbit inference engine (.cursor/rules/playwright.mdc)

**/*.{ts,tsx,js}: Write concise, technical TypeScript/JavaScript with accurate typing in Playwright tests
Avoid code comments in the implementation

Files:

• packages/ui-client/src/components/Contextualbar/ContextualbarDialog.tsx
• apps/meteor/client/views/room/layout/RoomLayout.tsx

🧠 Learnings (2)

📚 Learning: 2026-03-27T14:52:56.865Z

Learnt from: dougfabris
Repo: RocketChat/Rocket.Chat PR: 39892
File: apps/meteor/client/views/room/contextualBar/Threads/Thread.tsx:150-155
Timestamp: 2026-03-27T14:52:56.865Z
Learning: In Rocket.Chat, there are two different `ModalBackdrop` components with different prop APIs. During review, confirm the import source: (1) `rocket.chat/fuselage` `ModalBackdrop` uses `ModalBackdropProps` based on `BoxProps` (so it supports `onClick` and other Box/DOM props) and does not have an `onDismiss` prop; (2) `rocket.chat/ui-client` `ModalBackdrop` uses a narrower props interface like `{ children?: ReactNode; onDismiss?: () => void }` and handles Escape keypress and outside mouse-up, and it does not forward arbitrary DOM props such as `onClick`. Flag mismatched props (e.g., `onDismiss` passed to the fuselage component or `onClick` passed to the ui-client component) and ensure the usage matches the correct component being imported.

Applied to files:

• packages/ui-client/src/components/Contextualbar/ContextualbarDialog.tsx
• apps/meteor/client/views/room/layout/RoomLayout.tsx

📚 Learning: 2026-05-06T12:21:44.083Z

Learnt from: juliajforesti
Repo: RocketChat/Rocket.Chat PR: 40256
File: apps/meteor/client/components/CreateDiscussion/CreateDiscussion.tsx:121-149
Timestamp: 2026-05-06T12:21:44.083Z
Learning: Field wrappers in rocket.chat/fuselage-forms (Field, FieldLabel, FieldRow, FieldError, FieldHint) auto-create htmlFor/id associations, aria-describedby, and role="alert" for errors. Do not manually set htmlFor, id, aria-describedby, or role attributes when using these wrappers. This automatic wiring does not apply to plain rocket.chat/fuselage components, which require explicit ID wiring per the accessibility docs. In code reviews, prefer using fuselage-forms wrappers for form fields and verify there is no unnecessary manual ID/aria wiring in files that use these wrappers. If a component uses plain fuselage components, ensure proper id wiring as per docs.

Applied to files:

• packages/ui-client/src/components/Contextualbar/ContextualbarDialog.tsx
• apps/meteor/client/views/room/layout/RoomLayout.tsx

[cubic-dev-ai]

2 issues found across 2 files

<sub>Reply with feedback, questions, or to request a fix.

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