fix(desktop): mouse back and forward stay inside the browser tab#33276

[GPT-6.1 Sol][Codex] on behalf of shivam.

Handoff from the issue-watch investigation at main c73b38b379542cde87ec8bc855b70e7fae78fb5c:

• Not reproduced. We stopped before creating the two test threads or opening a Browser guest. No thumb-button input was sent, no regression tests ran, and we did not test this PR.
• On physical corex, Ubuntu Linux x86_64, vp run build:desktop passed, reporting 5/5 successful, with Node 26.12.1. The first attempt under Node 22.22.1 failed with ERR_UNKNOWN_FILE_EXTENSION for packages/shared/src/devProxy.ts.
• The built Electron 44.10.1 desktop app launched through native Ozone Wayland using an isolated headless Sway compositor and test profile. DISPLAY was unset; the runtime log showed actual Wayland surface traffic. This confirms a native Wayland test environment is available on corex, but it does not exercise the reporter's GNOME compositor.
• Read-only tracing found the preload runs only in the main frame and that Chromium's unconsumed thumb-button release navigates the outermost WebContents, consistent with the iframe path described here. We did not establish the reporter's plain-content Wayland trigger.

No before/after recording or navigation evidence was captured. All task-owned processes and the host test directory have been cleaned up; no source changes or pushes were made.

Explain Change →

No actionable comments were generated in the recent review.

• Autofix · Keep fixing CodeRabbit findings and required CI, and resolving merge conflicts

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• Source mode: Auto
• Repository: pingdotgg/t3code
• Branch: fix/issue-33259
• File: .coderabbit.config.ts
• Commit: 3855794
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• Run ID: c6356ac4-b566-40aa-8c84-1a5b070312fc

External image Commits

Reviewing files that changed from the base of the PR and between 1e13ec05da82592718baae75094cc24714bf6f29 and 385579457add6399b53fc79cfc2f01309346250d.

External image Files selected for processing: 1

• apps/desktop/src/preview/PickPreload.ts

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Approvability

Verdict: Approved at 4e58cde

Macroscope's review found this PR approvable — Mouse back and forward now navigate the preview tab rather than the host application, while preserving input and recording-cursor feedback. The change is narrowly scoped to existing preview gestures and introduces no material operational or data risk.

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Evidence

Both sides: real Electron 44.10.1 on Linux X11 under headless-desktop, 1600×900 window, light theme, fresh isolated databases and identical synthetic seeds. Native XTest mouse buttons 8/9; no DOM-dispatched mouse events. Recordings exclude the composer and mask fixture setup panels for privacy.

1. Open Thread A, then B. Open Browser p1 and click through to p2; both contain a same-origin iframe.
2. Hold/release Back inside the iframe, then hold/release Forward at the same coordinates.
3. Open A then B, replace the Browser fixture, clear its history, verify no Back/Forward history, and repeat both buttons.

Driver · RPC seed · Fixture server · Capture renderer · Reproduction notes · Base observations · Head observations

Boundary setup explicitly clears webview history because a newly opened tab retained an initial blank entry. Screenshots were taken after matching pixels 500 ms apart; recordings show the interaction. AI-assisted; verified with the tests and tools listed above.

Not shown:

• Physical mouse hardware was unavailable; native X11 XTest events exercised the real Electron input path.
• Cross-site iframes and main-frame content were not separately recorded; these runs cover same-origin iframe content.
• Guest recording-cursor replay, zoom-coordinate handling, ordinary mouse buttons, and other operating systems were not exercised.
• The no-history case was established with Electron webview.clearHistory(); a newly created tab alone retained an initial blank history entry.

Evidence

Real Linux X11 desktop app, Electron 44.10.1 / Chromium 152.0.7977.169, 1600×900, light theme, fresh synthetic data on each revision. Native XTEST buttons 8/9 were pressed and released separately. No DOM thumb events or navigation IPC were injected.

Same driver on both revisions: open A then B; Browser p1→p2; hold/release Back inside the iframe; reopen B unconditionally to inspect its preserved tab; hold/release Forward. Then create a new boundary tab, confirm Back is disabled, and hold/release Back inside its iframe. Repeat with cross-site and same-origin frames. Separate recordings exercise both thumb buttons with the real Preview menu and Browser recorder enabled.

Base changes chat to A on Back release while its tab remains on p2. Head keeps chat on B and navigates only the tab, on release. At either iframe history boundary, head leaves both surfaces unchanged. Cross-site frames were confirmed as separate iframe targets. Boundary clips include fresh-tab setup and the complete interaction, providing independent evidence.

On head, both consumed thumb presses dismiss the actual Preview menu and produce human-control plus recording down/up signals. The fixture HUD only mirrors genuine read-only desktopBridge events; it does not generate them. The rings above come from the app's exported video.

Capture driver, seed, fixture and reproduction instructions.

Supporting observations: base navigation, head navigation, base cross-site targets, head cross-site targets, base thumb events, head thumb events.