Prevent macOS dock miniwindow preview from rendering blank

[Copilot]

On macOS, the Dock preview (miniwindow image) could intermittently disappear after minimizing, while the app itself remained functional. Reopening and re-minimizing temporarily restored it, indicating unstable preview capture during miniaturization.

• Root cause mitigation: deterministic miniwindow image

  • Added windowWillMiniaturize(_:) in AppDelegate to capture window content immediately before minimize.
  • Explicitly assigns the captured image to NSWindow.miniwindowImage, avoiding reliance on inconsistent implicit snapshotting.

• Supporting utility: view snapshot helper

  • Added a private NSView.snapshotImage() helper that:
    • guards zero-size bounds,
    • caches display into a bitmap representation,
    • returns an NSImage suitable for Dock miniwindow usage.

func windowWillMiniaturize(_ notification: Notification) {
    guard
        let miniaturizingWindow = notification.object as? NSWindow,
        let image = miniaturizingWindow.contentView?.snapshotImage()
    else { return }

    miniaturizingWindow.miniwindowImage = image
}

[deepsource-io]

DeepSource Code Review

We reviewed changes in 35a6fce...342c9e3 on this pull request. Below is the summary for the review, and you can see the individual issues we found as inline review comments.

See full review on DeepSource ↗

PR Report Card

Overall Grade

Security   Reliability   Complexity   Hygiene

Code Review Summary

Analyzer	Status	Updated (UTC)	Details
Rust		Jun 1, 2026 12:22p.m.	Review ↗

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