Fix window position restore on relaunch - #2129

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Project	Deployment	Actions	Updated (UTC)
cmux	Ready	Preview, Comment	Mar 25, 2026 8:55am

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Greptile Summary

This PR fixes issue #2126 by stopping the unnecessary clamping of saved window frames when display geometry changes only slightly (e.g., dock or menu bar height adjusts by a few pixels). It inserts a new shouldPreserveAccessibleFrame helper between the existing visibleFrame.intersects guard and the clampFrame call: if a sufficient portion of the window's title bar (top 64 pt strip) is still reachable inside the current display's visible frame, the saved frame is returned exactly. Frames whose title bar has slipped off-screen still fall through to the existing clampFrame / remappedFrame recovery paths unchanged.

Key highlights:

• shouldPreserveAccessibleFrame validates that at least 120 × 24 pt of the top strip is visible — sensible defaults for a draggable title bar region.
• The regression test follows the CLAUDE.md two-commit structure (30b2c8af adds the failing test, f2bc1392 adds the fix), so CI history proves the test was red before the fix.
• The guard inside shouldPreserveAccessibleFrame uses targetDisplay.frame (physical bounds) rather than targetDisplay.visibleFrame; since the call-site already guarantees visibleFrame.intersects(frame), this guard is always satisfied — a minor redundancy but not a bug.
• Off-screen recovery behavior (remap / center) is unchanged.

Confidence Score: 5/5

• Safe to merge — the fix is well-scoped, regression-tested, and leaves the existing off-screen recovery path intact.
• The logic is correct: the title-bar-strip check accurately distinguishes accessible frames from inaccessible ones. The two-commit test structure provides CI-verified regression coverage. The only open item is a style-level redundancy in the guard condition that does not affect correctness.
• No files require special attention.

Important Files Changed

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[resolvedWindowFrame public entry] --> B{targetDisplay found?}
    B -- Yes --> C{shouldPreserveExactFrame - same displayID and geometry unchanged}
    C -- Yes --> D[Return frame as-is]
    C -- No --> E[resolvedWindowFrame private inner]
    E --> F{visibleFrame intersects frame?}
    F -- Yes --> G{shouldPreserveAccessibleFrame - 120x24pt of top strip visible}
    G -- Yes --> H[Return frame as-is - NEW]
    G -- No --> I[clampFrame within visibleFrame]
    F -- No --> J{displaySnapshot available?}
    J -- Yes --> K[remappedFrame from saved to current display]
    J -- No --> L[centeredFrame in targetDisplay]
    B -- No --> M{Any display intersects frame?}
    M -- Yes --> N[clampFrame within that display]
    M -- No --> O[remap or center in fallbackDisplay]

_{Reviews (1): Last reviewed commit: "Merge branch 'main' of https://github.co..." | Re-trigger Greptile}