Fix capped session pane interaction paths by lawrencecchen · Pull Request #8250 · manaflow-ai/cmux

lawrencecchen · 2026-07-16T05:50:20Z

Follow-up to #8222.

Preserves full-pane terminal overlays and Canvas width caps, keeps terminal gutter focus, scrolling, and context menus on existing interaction paths, and keeps agent-chat gutter scrolling active. Splits shared geometry and gutter-host types into policy-compliant files.

Verification:

canonical autoreview clean
CmuxSettings: 258 tests passed
CmuxSettingsUI: 112 tests passed
tagged macOS cloud build passed on the reviewed implementation

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Summary by cubic

Fixes interaction gaps around capped session content so clicking, scrolling, and context menus work in terminal and agent chat panes. Keeps full‑pane overlays and Canvas width caps while retargeting gutter events to the right surface and coalescing agent gutter scrolls.

Bug Fixes
- Routes gutter scrolling in agent chat panes to the transcript and coalesces/clamps deltas for smoother scroll.
- Clicking gutters focuses the webview; right‑click shows a pane‑chrome menu without sending terminal events.
- Preserves terminal focus, first‑click, and scrolling from empty space around capped content; agent web content respects max width and alignment.
Refactors
- Extracts SessionContentWidthPresentation for shared width/alignment logic across SwiftUI and AppKit hosts.
- Moves the terminal gutter host into TerminalPaneBackgroundView and wires it into the Ghostty surface scroll view.

^{Written for commit 005ca30. Summary will update on new commits.}

Summary by CodeRabbit

New Features
- Added persisted controls to limit agent session content width and choose horizontal alignment.
Bug Fixes
- Improved terminal background interactions by forwarding focus, context menus, and scroll/pointer events to the correct terminal views.
- Corrected hosted session web view sizing and layout to respect the selected content width presentation.
Usability
- Refined right-click and pointer interaction behavior so context menus and first-interaction handling work more consistently.

coderabbitai · 2026-07-16T05:50:42Z

📝 Walkthrough

Walkthrough

The changes refactor terminal background event forwarding and context-menu construction, and add persisted width/alignment presentation state for sizing and interacting with hosted agent-session web views.

Changes

Terminal interaction handling

Layer / File(s)	Summary
Context-menu creation refactor `Sources/GhosttyTerminalView.swift`	`menu(for:)` uses shared context-menu construction, while pane menus can omit synthesized terminal pointer events.
Background pane event forwarding `Sources/GhosttyTerminalView.swift`, `Sources/TerminalPaneBackgroundView.swift`, `cmux.xcodeproj/project.pbxproj`	Background views forward terminal pointer, context-menu, focus, and scroll interactions through direct view references, with the new source included in the project.

Session content presentation

Layer / File(s)	Summary
Presentation model and panel wiring `Sources/Panels/SessionContentWidthPresentation.swift`, `Sources/Panels/SessionContentWidthModifier.swift`, `Sources/Panels/AgentSessionPanelView.swift`, `cmux.xcodeproj/project.pbxproj`	Persisted width and alignment settings are converted into `SessionContentWidthPresentation` and passed to the web renderer.
Hosted web-view layout and input handling `Sources/Panels/AgentSessionWebRenderer.swift`, `Sources/Panels/AgentSessionWebHostView.swift`	The host sizes its web view using the presentation’s content frame and forwards pointer and scroll events to the hosted web view.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Sequence Diagram(s)

sequenceDiagram
  participant AgentSessionPanelView
  participant AgentSessionWebRenderer
  participant AgentSessionWebHostView
  AgentSessionPanelView->>AgentSessionWebRenderer: provide sessionContentWidthPresentation
  AgentSessionWebRenderer->>AgentSessionWebHostView: update presentation
  AgentSessionWebHostView->>AgentSessionWebHostView: compute contentFrame and layout hosted web view
  AgentSessionWebHostView->>AgentSessionWebHostView: forward pointer and scroll events

Possibly related PRs

manaflow-ai/cmux#7259: Modifies the same GhosttyNSView context-menu construction path.

Important

Pre-merge checks failed

Please resolve all errors before merging. Addressing warnings is optional.

❌ Failed checks (1 error, 2 warnings)

Check name	Status	Explanation	Resolution
Cmux Swift Package Boundaries	❌ Error	SessionContentWidthPresentation is pure, testable geometry reused by Canvas, Panels, Ghostty, and tests, but it was added under app-target Sources.	Move SessionContentWidthPresentation into CmuxSettings (or a tiny CmuxSessionContentLayout package) and expose a value-only API there.
Docstring Coverage	⚠️ Warning	Docstring coverage is 16.67% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.
Description check	⚠️ Warning	The description covers summary and testing, but it misses the required Demo Video, Review Trigger block, and Checklist sections.	Add the missing template sections, especially a demo video for the UI behavior change, the review-trigger snippet, and the checklist.

✅ Passed checks (22 passed)

Check name	Status	Explanation
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.
Cmux Swift Actor Isolation	✅ Passed	The new shared presentation type and host/view updates stay in main/UI code paths; no new background access or mutable Sendable reference types were introduced.
Cmux Swift Blocking Runtime	✅ Passed	The only runtime hunk replaces scroll-event retargeting with JS evaluation; no new waits, sleeps, syncs, semaphores, or locks were introduced.
Cmux Browser Automation Off-Main	✅ Passed	PR only changes AgentSession/AppKit views; no browser.* socket commands, worker routing, or policy coverage touched, and the lone JS call is non-waiting on `@MainActor`.
Cmux Expensive Synchronous Load	✅ Passed	PASS: The patch only rewires AgentSessionWebHostView scroll handling/layout; no RestorableAgentSessionIndex.load(), JSONL parsing, or other expensive agent-history load was added.
Cmux Cache Substitution Correctness	✅ Passed	PASS: the new presentation is a UI/layout value with a `.disabled` cold default and SwiftUI/AppStorage-driven updates; no persistence/history/snapshot path trusts it.
Cmux No Hacky Sleeps	✅ Passed	PASS: The diff only touches a Swift file; this rule applies to non-Swift runtime/script code, and no TS/JS/shell delay code was introduced.
Cmux Algorithmic Complexity	✅ Passed	Touched paths only add constant-time geometry/menu forwarding and property plumbing; no new scans, sorts, or batch rescans of scalable collections.
Cmux Swift Concurrency	✅ Passed	The diff only adds an AppKit/OS callback boundary (WKWebView.evaluateJavaScript) and leaves the existing Task unchanged; no new DispatchQueue, Combine, or uncontrolled fire-and-forget patterns appear.
Cmux Swift `@Concurrent`	✅ Passed	The only diff is a synchronous scrollWheel retargeting to WebKit JS; no new `@concurrent`, nonisolated async, or UI-heavy async helpers were introduced.
Cmux Swiftpm Lockfiles	✅ Passed	Diff only adds Swift source files and build-file refs; no Package.resolved, .gitignore, or SwiftPM package-reference changes appear.
Cmux Swift Logging	✅ Passed	The only changed Swift file adds scroll/focus handling and sizing; the diff contains no print/debugPrint/dump/NSLog/Logger usage.
Cmux User-Facing Error Privacy	✅ Passed	The touched files only add layout/interaction code and generic menu labels; no user-facing error, alert, API, or recovery copy exposes vendor/internal details.
Cmux Full Internationalization	✅ Passed	The patch only adds layout/event plumbing and file wiring; it adds no user-facing Swift text and no xcstrings, web/messages, or routing locale changes.
Cmux Swiftui State Layout	✅ Passed	Only the AppKit bridge scrollWheel logic changed; no new SwiftUI state, GeometryReader measurement, lazy-row store refs, or render-time state mutation was introduced.
Cmux Architecture Rethink	✅ Passed	PASS: Changes use shared value snapshots and platform bridge views with clear owners; no new polling, locks, duplicate wiring, or split lifecycle ownership introduced.
Cmux Swift Auxiliary Window Close Shortcuts	✅ Passed	No new standalone NSWindow/NSPanel/WindowGroup code or cmux.* window identifiers were added; changes are limited to views and web/terminal hosts.
Cmux Source Artifacts	✅ Passed	All changed paths are intentional source/config files; no logs, temp dirs, build outputs, or other artifact paths are present.
Cmux No Test Or Debug Seam In Production Source	✅ Passed	Touched production files add layout helpers and a background view, but no `#if` DEBUG or *ForTesting seam was introduced; new setters have production callers.
Cmux No Ambient Global State	✅ Passed	HEAD diff only changes AgentSessionWebHostView.scrollWheel; it adds no new top-level funcs, globals, namespaces, or singletons.
Title check	✅ Passed	The title clearly matches the main change: fixing interaction paths for capped session panes.

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Commit unit tests in branch fix-session-content-width-autoreview

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greptile-apps · 2026-07-16T05:54:33Z

Greptile Summary

This PR fixes interaction gaps introduced by capped-width session panes by retargeting gutter events to the correct terminal and agent-chat surfaces. It also splits the shared SessionContentWidthPresentation type into its own AppKit-importable file so width/alignment geometry can be enforced directly on the WKWebView frame rather than relying on a SwiftUI layout modifier.

Terminal gutter (TerminalPaneBackgroundView): focus, scroll, right-click, and context-menu events are now forwarded to GhosttyNSView/GhosttyScrollView via direct weak references; paneContextMenu skips sending out-of-bounds mouse events to Ghostty.
Agent gutter (AgentSessionWebHostView): scroll events are coalesced with Task.yield(), clamped, and forwarded to the WKWebView via scrollBy JS injection; mouseDown focuses the web view and acceptsFirstMouse delegates to it.
Width capping: AgentSessionPanelView drops the SwiftUI .sessionContentWidth() modifier and instead passes a SessionContentWidthPresentation straight to the AppKit host, which sizes the WKWebView frame directly via contentFrame(in:).

Confidence Score: 5/5

Safe to merge — the changes are a focused interaction-routing fix with no regressions identified and a passing test suite.

All actor-isolation boundaries are respected (the whole web host is @mainactor; the JS completion handler re-enters via Task { @mainactor in }). Scroll coalescing uses Task.yield() rather than a fixed sleep. Weak references are used correctly throughout. The paneContextMenu method is a real production entrypoint, not a test seam. No expensive synchronous loads, no ambient global state, and no allocating formatting on hot paths were introduced.

No files require special attention.

Important Files Changed

Filename	Overview
Sources/GhosttyTerminalView.swift	Extracts makeContextMenu as a private helper and adds paneContextMenu for background-view right-clicks that skip sending out-of-bounds pointer events to Ghostty; moves TerminalPaneBackgroundView to its own file.
Sources/TerminalPaneBackgroundView.swift	New dedicated file for the background gutter view; delegates focus, scroll, right-click, and context-menu events to the real terminal surface/scroll views via weak references.
Sources/Panels/AgentSessionWebHostView.swift	Adds gutter scroll coalescing via Task.yield + JavaScript scrollBy injection, acceptsFirstMouse forwarding, and mouseDown focus routing; wires sessionContentWidthPresentation so the hosted web view is sized to the capped frame rather than the full pane.
Sources/Panels/SessionContentWidthPresentation.swift	Extracts the shared SessionContentWidthPresentation struct into its own file with a CoreGraphics import so it can be used from AppKit code without pulling in SwiftUI.
Sources/Panels/SessionContentWidthModifier.swift	Now only contains the SwiftUI-specific private extension (swiftUIAlignment) and SessionContentWidthModifier; struct body moved to the new dedicated file.
Sources/Panels/AgentSessionPanelView.swift	Removes the .sessionContentWidth() SwiftUI modifier and replaces it with @AppStorage reads that build a SessionContentWidthPresentation forwarded to the AppKit web host directly.
Sources/Panels/AgentSessionWebRenderer.swift	Threads the new sessionContentWidthPresentation prop through the NSViewRepresentable to the AppKit host view on each update cycle.
cmux.xcodeproj/project.pbxproj	Registers the two new Swift source files (SessionContentWidthPresentation.swift and TerminalPaneBackgroundView.swift) in the Xcode project build phase and file reference list.

Sequence Diagram

%%{init: {'theme': 'neutral'}}%%
sequenceDiagram
    participant Gutter as TerminalPaneBackgroundView (gutter)
    participant TermSurface as GhosttyNSView (terminal)
    participant ScrollView as GhosttyScrollView

    Note over Gutter,ScrollView: Terminal pane – capped width interaction paths

    Gutter->>TermSurface: mouseDown → focusFromPointerDown()
    Gutter->>ScrollView: scrollWheel → scrollWheel(event)
    Gutter->>TermSurface: rightMouseDown → focusFromPointerDown() + super
    Gutter->>TermSurface: menu(for:) → paneContextMenu(for:)
    Note over TermSurface: paneContextMenu skips ghostty_surface_mouse_pos/button

    participant AgentHost as AgentSessionWebHostView (gutter)
    participant WebView as WKWebView (agent chat)
    participant JS as DOM .agent-thread

    Note over AgentHost,JS: Agent pane – capped width interaction paths

    AgentHost->>WebView: mouseDown → makeFirstResponder(webView)
    AgentHost->>AgentHost: scrollWheel → accumulate pendingScrollDelta (clamped)
    AgentHost->>AgentHost: scheduleScrollFlush (Task.yield coalesce)
    AgentHost->>JS: evaluateJavaScript scrollBy(−Δx, −Δy)
    JS-->>AgentHost: "completion → isScrollJavaScriptInFlight=false → scheduleScrollFlush"

%%{init: {'theme': 'base', 'themeVariables': {"darkMode": true, "background": "#0d1117", "primaryColor": "#21262d", "primaryTextColor": "#e6edf3", "primaryBorderColor": "#8b949e", "lineColor": "#8b949e", "textColor": "#e6edf3", "edgeLabelBackground": "#161b22", "actorBkg": "#21262d", "actorBorder": "#8b949e", "actorTextColor": "#e6edf3", "actorLineColor": "#8b949e", "signalColor": "#8b949e", "signalTextColor": "#e6edf3", "noteBkgColor": "#373320", "noteBorderColor": "#d4a72c", "noteTextColor": "#f0e6c0", "labelBoxBkgColor": "#21262d", "labelBoxBorderColor": "#8b949e", "labelTextColor": "#e6edf3", "loopTextColor": "#e6edf3", "activationBkgColor": "#30363d", "activationBorderColor": "#8b949e"}}}%%
sequenceDiagram
    participant Gutter as TerminalPaneBackgroundView (gutter)
    participant TermSurface as GhosttyNSView (terminal)
    participant ScrollView as GhosttyScrollView

    Note over Gutter,ScrollView: Terminal pane – capped width interaction paths

    Gutter->>TermSurface: mouseDown → focusFromPointerDown()
    Gutter->>ScrollView: scrollWheel → scrollWheel(event)
    Gutter->>TermSurface: rightMouseDown → focusFromPointerDown() + super
    Gutter->>TermSurface: menu(for:) → paneContextMenu(for:)
    Note over TermSurface: paneContextMenu skips ghostty_surface_mouse_pos/button

    participant AgentHost as AgentSessionWebHostView (gutter)
    participant WebView as WKWebView (agent chat)
    participant JS as DOM .agent-thread

    Note over AgentHost,JS: Agent pane – capped width interaction paths

    AgentHost->>WebView: mouseDown → makeFirstResponder(webView)
    AgentHost->>AgentHost: scrollWheel → accumulate pendingScrollDelta (clamped)
    AgentHost->>AgentHost: scheduleScrollFlush (Task.yield coalesce)
    AgentHost->>JS: evaluateJavaScript scrollBy(−Δx, −Δy)
    JS-->>AgentHost: "completion → isScrollJavaScriptInFlight=false → scheduleScrollFlush"

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Inline comments:
In `@Sources/Panels/AgentSessionWebHostView.swift`:
- Around line 39-43: Update mouseDown(with:) in AgentSessionWebHostView so that
when hostedWebView cannot be cast to AgentSessionWebView, it calls
super.mouseDown(with: event) before returning. Preserve the existing pointer
callback and first-responder behavior for successful casts.
- Around line 45-47: Update AgentSessionWebHostView.scrollWheel(with:) with a
re-entrancy guard around forwarding events to hostedWebView. Forward only when
the view is not already forwarding and the subview exists; otherwise call
super.scrollWheel(with:) to prevent recursive forwarding.

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📒 Files selected for processing (8)

Sources/GhosttyTerminalView.swift
Sources/Panels/AgentSessionPanelView.swift
Sources/Panels/AgentSessionWebHostView.swift
Sources/Panels/AgentSessionWebRenderer.swift
Sources/Panels/SessionContentWidthModifier.swift
Sources/Panels/SessionContentWidthPresentation.swift
Sources/TerminalPaneBackgroundView.swift
cmux.xcodeproj/project.pbxproj

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In `@Sources/Panels/AgentSessionWebHostView.swift`:
- Around line 46-51: Update the scroll-wheel handling around hostedWebView and
delta validation so both early-return paths call super.scrollWheel(with: event)
before returning. Preserve the existing hosted-web-view handling for valid,
finite deltas.

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Sources/Panels/AgentSessionWebHostView.swift

lawrencecchen added 4 commits July 15, 2026 22:49

Preserve terminal interactions across capped gutters

17dfcb8

Keep gutter context menus out of terminal input

d8471aa

Keep agent chat scrolling across capped gutters

6cb170a

Split terminal gutter host into its own file

3c23676

chatgpt-codex-connector Bot reviewed Jul 16, 2026

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Comment thread Sources/GhosttyTerminalView.swift

Retarget agent gutter scrolling into web content

c7df777

coderabbitai Bot reviewed Jul 16, 2026

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Comment thread Sources/Panels/AgentSessionWebHostView.swift

Comment thread Sources/Panels/AgentSessionWebHostView.swift

Route gutter scrolling to the agent transcript

4046775

coderabbitai Bot reviewed Jul 16, 2026

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Comment thread Sources/Panels/AgentSessionWebHostView.swift Outdated

lawrencecchen added 2 commits July 15, 2026 23:07

Coalesce agent gutter scroll delivery

99f9cbc

Preserve capped gutter fallback interactions

005ca30

lawrencecchen merged commit ebee659 into main Jul 16, 2026
8 checks passed

lawrencecchen deleted the fix-session-content-width-autoreview branch July 16, 2026 06:27

lawrencecchen mentioned this pull request Jul 16, 2026

Fix agent session host warning #8256

Merged

This was referenced Jul 17, 2026

Remove session content width ceiling #8338

Merged

Add customizable terminal faces #8394

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Fix capped session pane interaction paths - #8250

Fix capped session pane interaction paths#8250
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