Files on Linux (2.57)

Targeted fixes for portal pick / drop / reveal footguns on Linux — building on 1.68 / 1.79 / 2.53 field data.

Related: platform-linux-wayland.md · system-integration.md · drag-drop.md

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Goal

Product apps ship FilePicker, FileDropZone, and reveal-in-folder on Linux but hit three recurring failures: missing parent window, reveal opens wrong/no folder, and silent drop reject. 2.57 closes the top three with small platform + control fixes.

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Top 3 footguns (fixed in 2.57)

#	Symptom	Cause	Fix
1	File dialog not modal on Wayland	FilePicker.* called without Window.window	Focus/visible window fallback via LinuxPortal::resolveParentObject; still warn when parent_window empty
2	Reveal after Save does nothing (GNOME)	OpenURI fallback had no portal parent	revealFileInFolder(path, Window.window) passes parent_window to portal
3	Drop looks broken — no feedback	MIME/extension reject with no chrome change	FileDropZone.isDragRejected + dragRejected signal

Out: Full xdg-foreign on every Qt build; Flatpak sandbox policy; WebView2 download presets (defer).

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Deliverables

Item	Location
Parent fallback	LinuxPortal::resolveParentObject · FilePicker portal path
Reveal parent	WindowHelper.revealFileInFolder(path, parentWindow?)
Drop reject UX	FileDropZone: isDragRejected, border highlight
Field matrix bump	platform-linux-wayland.md 2.57
Gallery refresh	System integration · FileDropZone · Pitfalls 2.57

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App checklist

• [ ] Always pass Window.window to FilePicker.open* / saveFile / openFolder
• [ ] After save: WindowHelper.revealFileInFolder(path, Window.window)
• [ ] FileDropZone: set acceptExtensions + acceptMimeTypes; handle dragRejected
• [ ] Same ingest function for drop and browse — drag-drop.md
• [ ] Bootstrap: QWinUI3::configureEnvironment before QGuiApplication
• [ ] Field soak: KDE Plasma Wayland + GNOME — platform-linux-wayland.md regression suite

Next: 2.58 OSK in apps · 2.59 named slow flows