[BUG] macOS: fullscreen window in a separate Space disappears permanently after clicking "Check for Updates"

[qieyuanwanhua]

Issue type

Desktop client (macOS) / auto-update button

Environment

Item	Value
App	DeepSeek Harness (desktop)
App version	0.2.0-rc.2 (CFBundleVersion: 0.2.0-rc.2)
Embedded runtime	Electron 44.0.0
OS	macOS 27.0.1 (Build 26A434)
Model	MacBook Air (Mac17,3, MDHE4CH/A)
Chip	Apple M5 (10 cores: 4 performance + 6 efficiency)
Memory	16 GB
Architecture	arm64 (Apple Silicon)

Steps to reproduce

1. Launch DeepSeek Harness (desktop).
2. Put the window into fullscreen and place it in a separate display/Space (e.g. it gets moved to the Space of another display after going fullscreen, or drag it to another Space via Mission Control).
3. Click the menu bar → "Check for Updates".
4. The whole window disappears immediately.

Actual behavior

• The window disappears completely and is not shown in the Dock / app switcher (or switching to it still shows no window).
• No way to recover it has been found: clicking the Dock icon again, Cmd+Tab, and moving windows all fail to bring it back.
• This bug does not trigger when the window is not fullscreen.

[xinnian999]

Cross-reference: the same root cause is analysed in #8224 — I added a detailed root-cause comment there: #8224 (comment)

Short version, in case it helps this thread:

• The update prompt is not a native sheet on darwin but a transparent frameless child window covering the parent's content area (apps/desktop/src/update-overlay.ts:27, transparent: true, called with nativeModal=false). On confirm it hides the card and calls destroy() 150 ms later (apps/desktop/src/update-dialog.ts).
• The parent window itself is vibrancy: 'sidebar' + backgroundColor: '#00000000' (apps/desktop/src/main.ts:224 / :228), and both are re-assigned at runtime by applyBackdrop() on minimize / hide / restore / show (main.ts:262-275), flipping the window between an opaque fallback fill and a fully transparent background.
• Nothing forces the parent window to repaint after the child overlay is destroyed (no invalidate-like call anywhere in the repo).

That is most likely why the three reports only differ in how the parent window is lost: content stays in place but renders black (standard fullscreen — #8224 and my own run), or the window is not shown at all (fullscreen in a separate Space — this thread).

One more data point for this thread, without a separate Space: on 0.2.0-rc.2, fullscreen → menu bar "Check for Updates" → confirm → the window goes black but still receives clicks (renderer process alive, main process not hung), unrecoverable without quitting. Same path is shared by "About DeepSeek Harness" (showAbout → ordinaryMessageBox → updateDialog.show), so that menu item is affected too.

Still present in the newest release: dsh-v0.2.1-alpha.2 (2026-10-09) ships byte-identical apps/desktop/src/main.ts, update-overlay.ts and update-dialog.ts compared with master, so upgrading does not avoid it. update-overlay.ts was last touched 2026-09-23 and update-dialog.ts 2026-09-24, both before the first report (2026-09-29).