Native windows: right-click menu downloads save, "in New Window" items tell the truth

[vasu2001]

What

In a native window (macOS) the right-click menu is WebKit's default — a browser's. Two of its items silently did nothing:

• Download Image / Download Linked File / Download Media — context-menu downloads bypass the public didBecomeDownload hooks and arrive through the private _webView:contextMenuDidCreateDownload:. Nobody adopted the WKDownload, so it had no delegate to pick a destination. Now adopted like a link download: ~/Downloads, Finder-style unique name, Dock bounce.
• Open Image / Link / Media in New Window — goes through the popup delegate. An external http(s) URL went to the default browser (worked, label lied); a blob: / data: URL (a generated image) had nowhere to go. The proposed menu is now curated through _webView:getContextMenuFromProposedMenu:forElement:userInfo:completionHandler::
  • external URL → retitled "… in Browser"
  • URL on our own server → kept as is (opens a native window)
  • anything else (blob:, data:) → dropped; Copy Image and Download Image remain

Decisions are pure Python in window_policy.context_menu_item; mac_window.py enacts them. The menu is left exactly as proposed when WebKit offers no hit-test URLs (never curate blind).

Notes

• Both hooks are private WebKit selectors, same precedent as pointer lock / geolocation already in mac_window.py; DMG build, not App Store.
• Menu item identifiers (WKMenuItemIdentifierOpenImageInNewWindow etc.) come from WKMenuItemIdentifiersPrivate.h, which the SDK doesn't ship — verify live that the retitle/drop lands on the image item.
• Same fix goes to fused-bot (mainwindow.py) in a sibling PR.

Verify

1. Native window → an app with a generated (blob/data) image → right-click: no "Open Image in New Window"; Download Image saves into ~/Downloads.
2. Right-click an https:// image or link: item reads "Open Image in Browser" / "Open Link in Browser" and opens the default browser.
3. Right-click an app-served image (http://127.0.0.1:<port>/…): item still reads "Open Image in New Window" and opens a native window.

🤖 Generated with Claude Code

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Note

Medium Risk
Relies on undocumented WebKit selectors and menu item identifiers that may shift across OS versions; failures degrade to the default menu rather than crashing.

Overview
Native macOS windows now fix broken WebKit right-click behavior by hooking private delegate selectors (same pattern as pointer lock / geolocation).

Context-menu downloads (Download Image, linked file, media) are adopted via _webView:contextMenuDidCreateDownload: and routed through the existing ~/Downloads + unique-name path, instead of silently doing nothing.

“Open … in New Window” items are curated via _webView:getContextMenuFromProposedMenu:… using hit-test URLs and pure policy in window_policy.context_menu_item: loopback app URLs stay as-is; external http(s) labels become “… in Browser”; blob:/data: items are removed. If hit-test data is missing or curation throws, WebKit’s proposed menu is shown unchanged.

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