Fix Ctrl+wheel zoom in agent panes - #877
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Dinah Xiaoman G (DinahK-2SO) merged 4 commits intoSep 7, 2026
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Prioritize vertical Ctrl+wheel zoom for agent TermControls while preserving plain and horizontal VT mouse input. Add focused unit coverage and physical packaged E2E coverage with release checklist mapping. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Dinah Xiaoman G (DinahK-2SO)
September 7, 2026 04:04
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🟡 Changes recommended
The new Win32 GetCursorPos P/Invoke is missing SetLastError=true, so failures can report incorrect Win32 error codes in the new wheel-injection helper.
Once you've addressed the issues Copilot identified, you can request another Copilot review.
Pull request overview
Fixes Ctrl+mouse-wheel zoom behavior in agent panes by letting agent TermControls prioritize zoom handling before VT mouse tracking consumes vertical Ctrl+wheel, while keeping plain wheel and horizontal wheel routed to the agent as before.
Changes:
- Add an agent-only “prioritize zoom on Ctrl+vertical wheel” path in
ControlInteractivity::MouseWheel, wired throughTermControlvia a new opt-in flag. - Enable this behavior for agent panes and extend Control unit tests to cover VT-mouse-enabled routing vs. zoom priority.
- Add ItE2E support for physical wheel injection and an E2E + release-checklist case validating Ctrl+wheel zoom + plain wheel chat scrolling.
File summaries
| File | Description |
|---|---|
| test/e2e/tests/Feature.AgentMouse.Tests.ps1 | Adds a physical wheel routing E2E validating plain wheel scroll + Ctrl+wheel zoom in agent panes. |
| test/e2e/README.md | Updates E2E suite table entry and coverage/test-status counts to include the new case. |
| test/e2e/ItE2E/Public/Ui.ps1 | Adds Win32 SendInput-based physical wheel injection helper (Invoke-WtWindowWheel). |
| test/e2e/ItE2E/ItE2E.psm1 | Exports Invoke-WtWindowWheel from the ItE2E module. |
| src/cascadia/UnitTests_Control/ControlInteractivityTests.cpp | Adds a unit test ensuring agent-pane Ctrl+wheel zoom happens before VT mouse wheel routing. |
| src/cascadia/TerminalControl/TermControl.idl | Introduces EnableAgentMouseWheelZoom API to opt TermControl into the new behavior. |
| src/cascadia/TerminalControl/TermControl.h | Stores the per-control agent zoom-priority flag. |
| src/cascadia/TerminalControl/TermControl.cpp | Passes the new flag into interactivity mouse-wheel handling paths. |
| src/cascadia/TerminalControl/ControlInteractivity.h | Adds a MouseWheel(..., bool prioritizeZoom) overload. |
| src/cascadia/TerminalControl/ControlInteractivity.cpp | Implements the zoom-priority fast path ahead of VT mouse routing when enabled. |
| src/cascadia/TerminalApp/AgentPaneContent.cpp | Enables the agent zoom-priority flag on agent-pane TermControls. |
| doc/release-check-list.md | Adds release-checklist case C295 covering physical Ctrl+wheel zoom in agent panes. |
Review details
- Files reviewed: 12/12 changed files
- Comments generated: 1
- Review effort level: Lite
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Mark the P/Invoke as SetLastError-aware so failed cursor queries report the correct Win32 error. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Dinah Xiaoman G (DinahK-2SO)
September 7, 2026 04:13
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🔵 Needs a closer look
The new physical-wheel E2E path should include the same foreground/interactive-desktop skip gating used elsewhere to avoid flakiness in unattended or focus-contended runs.
Review details
Suppressed comments (2)
Previously missed (2) — in code that hasn't changed since the last review.
test/e2e/tests/Feature.AgentMouse.Tests.ps1:213
- This physical wheel test currently fails hard when the WT window cannot take foreground (locked desktop / competing foreground app), which can make the suite flaky in unattended runs. Mirror the existing hotkey/physical-input suites by skipping when Test-WtWindowKeyFocusable fails before sending wheel input.
test/e2e/ItE2E/Public/Ui.ps1:124 - Avoid the raw 0x0800 magic number for mouse-wheel injection; define and use a named constant so the SendInput flags are self-describing and less error-prone to extend (e.g., if adding HWHEEL later).
- Files reviewed: 12/12 changed files
- Comments generated: 0 new
- Review effort level: Lite
Skip the physical-wheel case when foreground focus is unavailable and name the Win32 wheel input flag. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Dinah Xiaoman G (DinahK-2SO)
September 7, 2026 04:23
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🔵 Needs a closer look
The updated E2E coverage counts in test/e2e/README.md leave a nearby sentence still referring to the old “147 implemented checklist items,” creating an inconsistency that should be corrected.
Review details
Suppressed comments (1)
Previously missed (1) — in code that hasn't changed since the last review.
test/e2e/README.md:64
- The updated coverage/test-status counts (148/150 and 128 baseline cases) are followed by a sentence that still says "The 147 implemented checklist items...", which is now inconsistent and can confuse readers tracking coverage.
- Files reviewed: 12/12 changed files
- Comments generated: 0 new
- Review effort level: Lite
Keep the implemented checklist total consistent with the updated 148-of-150 summary. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Dinah Xiaoman G (DinahK-2SO)
September 7, 2026 04:32
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🟢 Approval recommended
The behavior change is narrowly gated to agent panes, and the PR adds both unit and physical E2E coverage plus a release-checklist item for the regression.
Review details
- Files reviewed: 12/12 changed files
- Comments generated: 0 new
- Review effort level: Lite
haonanttt
approved these changes
Sep 7, 2026
Kai Tao (vanzue)
approved these changes
Sep 7, 2026
Yuandi (DDKinger)
approved these changes
Sep 7, 2026
Kai Tao (vanzue)
deleted the
user/DinahK-2SO/agent-pane-zooming-publish
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September 7, 2026 05:36
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Summary of the Pull Request
Makes Ctrl+mouse-wheel zoom text in agent panes before VT mouse tracking can consume the event. Plain and horizontal wheel input still reaches the agent, while ordinary terminal and Ctrl+Shift opacity behavior remain unchanged.
References and Relevant Issues
Closes #790
Detailed Description of the Pull Request / Additional comments
Agent panes run a mouse-tracking TUI, so the existing VT-first wheel route consumed Ctrl+wheel as chat scrolling. Agent TermControls now opt into a vertical Ctrl+wheel priority path. The default route remains unchanged. The PR also adds physical HWND wheel injection to ItE2E and release-checklist case C295.
Validation Steps Performed
PR Checklist