Davy7/26/2026, 2:54:16 AM

The "start hidden, show on first paint" protection was silently dead. `visible:
false` lived only in the base tauri.conf.json, but every platform override
redefines the whole `app.windows` array, and Tauri merges platform config with
RFC 7396 JSON Merge Patch — where an array in the patch replaces the base array
wholesale rather than merging per window. `visible` therefore fell back to its
default of true on every desktop platform (taking `center` with it), so the
window was on screen for the entire webview load and `window_ready` →
`window.show()` was a no-op. The exposed white frame came from the WebView's
default opaque white surface, reinforced on macOS by an NSWindow background of
`windowBackgroundColor` (near-white in Light appearance).

Repeat `visible:false`, `center`, and a dark `backgroundColor` in every platform
window object, pin the macOS NSWindow backing to the app shell's dark surface,
declare `color-scheme` so the engine's default canvas is dark before any CSS
loads, and render a dark app-shell skeleton instead of nothing while the library
probe is in flight. A Rust test asserts every platform window carries these keys
so the array-replacement trap cannot silently return.

Making the window genuinely start hidden exposed a latent defect in the reveal
path: the request was scheduled inside requestAnimationFrame, and macOS suspends
animation frames for a hidden WebView, so the app ran with no window at all
(verified against a dev build). Arm a short timer alongside the frame so the
reveal always goes out, with the frame still winning when frames are produced.

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

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