Fix #592: file dialogs on Linux no longer stop the window answering

VectorCraft asks for a path where it needs one and goes on with it at
once, so its file dialogs ran on the UI thread. Windows and macOS dialogs
run the window's events meanwhile; on Linux nothing answered the Wayland
compositor's pings while a dialog was open, and Hyprland offered to kill
the window as not responding.

- ui-egui `picks`: every file dialog (open, save, folder, place) goes
  through one place. With the host's `start_pick` (desktop Linux) the
  dialog shows on a thread of its own; what asked (the command, the
  dialog's OK, a panel's or dialog's button) gives up for now and runs
  again with the picked path when the dialog answers. Another dialog
  waits for the open one.
- The desktop app passes its window as the dialogs' parent on Linux (the
  portal can then associate its window, "Unhandled parent window type"
  before) and Windows; macOS shows them as before.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Cargo.lock

@@ -4312,8 +4312,10 @@ dependencies = [
  "rfd",
  "serde_json",
  "vectorcraft-engine",
+ "vectorcraft-text",
  "vectorcraft-ui-egui",
  "webbrowser",
+ "windows",
  "winit",
  "winresource",
 ]

ROADMAP.md

@@ -4,7 +4,7 @@ VectorCraft is a clean-room, open-source, pure-Rust reimplementation of the Adob
 
 This file tracks **how far we are and what's left**. Time estimates are wall-clock hours of continuous Claude Opus 5.5 agent work (including builds and the CI gate), given both for **one agent** and for **4–6 parallel agents** on disjoint crates. They are counted from the remaining work (see [Parity estimate](#parity-estimate)), calibrated against measured throughput, and updated as work lands.
 
-_Last updated: 2026-10-09 (after placed documents (File › Place of a `.vectorcraft` file, linked), M4.14–M4.98, M8.1–M8.20, M14.4–M14.7, the MCP prompts, resource templates, completions and logging, the 2026-10-07 issue fixes, the Layers panel rework and the 2026-10-08 community contributions: Pen and shape-tool modifiers, path editing, Layers, Artboards, Swatches/Brushes and dialogs, Japanese composition and PDF text, Hebrew/Arabic type, interface languages (Spanish among them), the font menu, saved selections, MCP and EPS, the missing-font export warning (#319), open paths in the Shape Builder (#374), PDF/`.ai` import keeping strokes live and hidden and nested layers (#372), per-corner Live Corners (#381), SVG type opening at the size it draws at (#396), the Wayland clipboard with copied-file paste (#398), ruler guides that can be selected, moved and deleted (#414), two batches of Preferences options that were stored but unused (#394), skeleton reads with `document.find` for large documents over MCP (#416) and anchors dragged with Direct Selection snapping to points, segments and smart guides, clipped SVG layers opening as clipping layers (#420), PDF/`.ai` layers read on pages of tens of millions of operators (#419), Document Color Mode putting RGB greys on the black plate on request and converting pattern tiles (#421) and movable dialogs with Offset Path's Joins dropdown (#423) and numeric fields scrubbed by dragging their label (#400), stroke weight presets in the stroke unit (#426), the Appearance panel's Opacity popup (#430), type on a path brackets, flip and Type on a Path Options that keep the type in place (#429), Layers rows dragged with a ghost and dropped on the trash or New Layer (#435), tool flyouts opening on a right or corner press (#436), tool flyouts torn off into floating toolbars (#437), the Shape Builder's erase mode deleting edges too (#439), installed fonts registered outside the font folders and fonts installed while the app runs listed in the font menus (#443), alike circular corners on rectangles that aren't square (#442), tool cursors as OS cursors so the pointer no longer trails over the canvas (#444), artboards copied and pasted with their art (#446), guides dragged out of the rulers snapping to the art's side midpoints and the artboards, artboard guides (#451), the toolbar's double arrow and Window › Toolbars › Double Column switching between one and two columns in any window height (#455), the Smart Guides display options and Snapping Tolerance (#394), Font Size and Leading combo boxes with preset lists in the Character and Properties panels and the Control bar (#458), screenshots pasted from the clipboard on macOS, Windows and the web (#457), the Properties panel's Fill and Stroke matching the Control bar's, Illustrator's Window menu panel keys (Shift+F7 for Align…) and Alt-wheel zoom whatever the wheel preference (Discord feedback), the point/area type widget (Discord feedback), groups in legacy Illustrator .ai files (Discord feedback), a rotating desktop log file (#465), image controls in the Control bar and Properties panel: Image Trace with its presets, Mask, Crop Image, Embed/Unembed, and an Image Trace object's preset, Expand and Release (Discord feedback), the Pen working as the Anchor Point tool with Alt held over a selected path's handles and anchors, and anchor buttons that convert, connect and cut paths at the selected anchors (Discord feedback), Japanese hanging punctuation (burasagari, #463), Escape leaving Presentation Mode with no screen mode saved across restarts, documents dropped on the desktop app opening as tabs of their own and a note that an `.ai` file's art off its artboards isn't in the part read (#472), Add/Delete Anchor Point tool icons drawn from the Pen tool's (#479), EPS import running more of PostScript Level 3 (patterns, Type 3 fonts, mesh shadings, masked images, VM and resource probes), and a preview that stands in saying why (Discord feedback, #466, #469, #474), chords with modifiers recorded in Edit › Keyboard Shortcuts (#487), Type Object Selection by Path Only (#394), Anti-aliased Artwork (#394), Show Pixel Grid (#394), pen and touch taps pressed and lifted within one frame clicking where they tapped and the Linux/Wayland pen-tablet workaround (#491), bounding-box resizes landing on the other objects' anchors and centres with labels, and the Rotate, Scale, Shear and Reflect tools snapping their drags (#482), Shift-drag marquees that toggle the objects or anchors they reach and a Lasso whose Alt subtraction keeps the rest of the selection (#483), the mouse wheel stepping the focused numeric field, the dialogs' and preferences' drag values made such fields (#485), Show The Home Screen When No Documents Are Open (#394), Numbers Without Units Are Points (#394), Auto-Collapse Iconic Panels (#394), the Contextual Task Bar moved by its handle and its More Options menu pinning and resetting its position, a designed macOS DMG windoLine truncated
+_Last updated: 2026-10-09 (after placed documents (File › Place of a `.vectorcraft` file, linked), M4.14–M4.98, M8.1–M8.20, M14.4–M14.7, the MCP prompts, resource templates, completions and logging, the 2026-10-07 issue fixes, the Layers panel rework and the 2026-10-08 community contributions: Pen and shape-tool modifiers, path editing, Layers, Artboards, Swatches/Brushes and dialogs, Japanese composition and PDF text, Hebrew/Arabic type, interface languages (Spanish among them), the font menu, saved selections, MCP and EPS, the missing-font export warning (#319), open paths in the Shape Builder (#374), PDF/`.ai` import keeping strokes live and hidden and nested layers (#372), per-corner Live Corners (#381), SVG type opening at the size it draws at (#396), the Wayland clipboard with copied-file paste (#398), ruler guides that can be selected, moved and deleted (#414), two batches of Preferences options that were stored but unused (#394), skeleton reads with `document.find` for large documents over MCP (#416) and anchors dragged with Direct Selection snapping to points, segments and smart guides, clipped SVG layers opening as clipping layers (#420), PDF/`.ai` layers read on pages of tens of millions of operators (#419), Document Color Mode putting RGB greys on the black plate on request and converting pattern tiles (#421) and movable dialogs with Offset Path's Joins dropdown (#423) and numeric fields scrubbed by dragging their label (#400), stroke weight presets in the stroke unit (#426), the Appearance panel's Opacity popup (#430), type on a path brackets, flip and Type on a Path Options that keep the type in place (#429), Layers rows dragged with a ghost and dropped on the trash or New Layer (#435), tool flyouts opening on a right or corner press (#436), tool flyouts torn off into floating toolbars (#437), the Shape Builder's erase mode deleting edges too (#439), installed fonts registered outside the font folders and fonts installed while the app runs listed in the font menus (#443), alike circular corners on rectangles that aren't square (#442), tool cursors as OS cursors so the pointer no longer trails over the canvas (#444), artboards copied and pasted with their art (#446), guides dragged out of the rulers snapping to the art's side midpoints and the artboards, artboard guides (#451), the toolbar's double arrow and Window › Toolbars › Double Column switching between one and two columns in any window height (#455), the Smart Guides display options and Snapping Tolerance (#394), Font Size and Leading combo boxes with preset lists in the Character and Properties panels and the Control bar (#458), screenshots pasted from the clipboard on macOS, Windows and the web (#457), the Properties panel's Fill and Stroke matching the Control bar's, Illustrator's Window menu panel keys (Shift+F7 for Align…) and Alt-wheel zoom whatever the wheel preference (Discord feedback), the point/area type widget (Discord feedback), groups in legacy Illustrator .ai files (Discord feedback), a rotating desktop log file (#465), image controls in the Control bar and Properties panel: Image Trace with its presets, Mask, Crop Image, Embed/Unembed, and an Image Trace object's preset, Expand and Release (Discord feedback), the Pen working as the Anchor Point tool with Alt held over a selected path's handles and anchors, and anchor buttons that convert, connect and cut paths at the selected anchors (Discord feedback), Japanese hanging punctuation (burasagari, #463), Escape leaving Presentation Mode with no screen mode saved across restarts, documents dropped on the desktop app opening as tabs of their own and a note that an `.ai` file's art off its artboards isn't in the part read (#472), Add/Delete Anchor Point tool icons drawn from the Pen tool's (#479), EPS import running more of PostScript Level 3 (patterns, Type 3 fonts, mesh shadings, masked images, VM and resource probes), and a preview that stands in saying why (Discord feedback, #466, #469, #474), chords with modifiers recorded in Edit › Keyboard Shortcuts (#487), Type Object Selection by Path Only (#394), Anti-aliased Artwork (#394), Show Pixel Grid (#394), pen and touch taps pressed and lifted within one frame clicking where they tapped and the Linux/Wayland pen-tablet workaround (#491), bounding-box resizes landing on the other objects' anchors and centres with labels, and the Rotate, Scale, Shear and Reflect tools snapping their drags (#482), Shift-drag marquees that toggle the objects or anchors they reach and a Lasso whose Alt subtraction keeps the rest of the selection (#483), the mouse wheel stepping the focused numeric field, the dialogs' and preferences' drag values made such fields (#485), Show The Home Screen When No Documents Are Open (#394), Numbers Without Units Are Points (#394), Auto-Collapse Iconic Panels (#394), the Contextual Task Bar moved by its handle and its More Options menu pinning and resetting its position, a designed macOS DMG windoLine truncated
 
 ## Where we are
 

apps/vectorcraft/Cargo.toml

@@ -19,6 +19,7 @@ windows7 = ["eframe/glow"]
 [dependencies]
 vectorcraft-engine = { workspace = true }
 vectorcraft-ui-egui = { workspace = true }
+vectorcraft-text = { workspace = true }
 eframe = { workspace = true, features = ["default_fonts", "wayland", "x11"] }
 egui = { workspace = true }
 serde_json = { workspace = true }
@@ -36,6 +37,11 @@ winit = { version = "0.30", default-features = false }
 [target.'cfg(windows)'.dependencies]
 clipboard-win = { workspace = true }
 
+# DirectWrite's system font collection (src/system_fonts.rs): fonts that font services such as
+# Adobe Fonts load in place (#579). MIT OR Apache-2.0, already in the build through accesskit.
+[target.'cfg(all(windows, not(target_vendor = "win7")))'.dependencies]
+windows = { version = "0.62", features = ["Win32_Graphics_DirectWrite"] }
+
 [target.'cfg(target_os = "macos")'.dependencies]
 # The macOS menu bar (src/mac_menu.rs): Tauri's menu crate, AppKit menus behind a safe API (no GTK
 # with default features off). Pinned exactly: review the diff before bumping.

apps/vectorcraft/src/main.rs

@@ -27,11 +27,14 @@ mod mac_menu;
 #[cfg(target_os = "macos")]
 mod open_documents;
 mod printing;
+#[cfg(all(windows, not(target_vendor = "win7")))]
+mod system_fonts;
 mod window;
 
 use vectorcraft_engine::Session;
 use vectorcraft_engine::cmd::fileio;
 use vectorcraft_ui_egui::graphics::GraphicsLoss;
+use vectorcraft_ui_egui::picks::PickRequest;
 use vectorcraft_ui_egui::{ClipboardProbeFactory, FilePick, Services, VectorcraftApp};
 
 struct App {
@@ -183,9 +186,22 @@ fn save_prefs(app: &VectorcraftApp) {
     }
 }
 
-/// A native file dialog showing `pick`'s file types, folder and suggested name.
-fn file_dialog(pick: &FilePick) -> rfd::FileDialog {
-    let d = pick.filters.iter().fold(rfd::FileDialog::new(), |d, (name, exts)| d.add_filter(*name, exts));
+/// The window file dialogs belong to.
+type Parent = Option<std::sync::Arc<winit::window::Window>>;
+
+/// A native file dialog for `request` over `parent` (Windows and Linux, where the portal then
+/// shows it over the window and keeps it in front; macOS shows them as before).
+fn file_dialog(request: &PickRequest, parent: &Parent) -> rfd::FileDialog {
+    let d = match parent {
+        Some(w) if !cfg!(target_os = "macos") => rfd::FileDialog::new().set_parent(&**w),
+        _ => rfd::FileDialog::new(),
+    };
+    let pick = match request {
+        PickRequest::Open(pick) | PickRequest::Save(pick) => pick,
+        PickRequest::OpenMany => return fileio::place_filters().fold(d.set_title("Place"), |d, (name, exts)| d.add_filter(name, exts)),
+        PickRequest::Folder => return d,
+    };
+    let d = pick.filters.iter().fold(d, |d, (name, exts)| d.add_filter(*name, exts));
     let d = match &pick.folder {
         Some(folder) => d.set_directory(folder),
         None => d,
@@ -193,6 +209,28 @@ fn file_dialog(pick: &FilePick) -> rfd::FileDialog {
     if pick.name.is_empty() { d } else { d.set_file_name(&pick.name) }
 }
 
+/// Show `dialog` for `request` (on the calling thread, until it closes) → the paths picked.
+fn show_dialog(dialog: rfd::FileDialog, request: &PickRequest) -> Vec<String> {
+    let paths = match request {
+        PickRequest::Open(_) => dialog.pick_file().into_iter().collect(),
+        PickRequest::OpenMany => dialog.pick_files().unwrap_or_default(),
+        PickRequest::Save(pick) => {
+            // The Templates folder may not exist yet.
+            if let Some(folder) = &pick.folder {
+                let _ = std::fs::create_dir_all(folder);
+            }
+            dialog.save_file().into_iter().collect()
+        }
+        PickRequest::Folder => dialog.pick_folder().into_iter().collect(),
+    };
+    paths.into_iter().map(|p| p.to_string_lossy().to_string()).collect()
+}
+
+/// Show the dialog for `request` over `parent` now → the paths picked.
+fn pick_now(request: PickRequest, parent: &Parent) -> Vec<String> {
+    show_dialog(file_dialog(&request, parent), &request)
+}
+
 /// File → Show in Folder: select `path` in Finder / Explorer, or open its folder elsewhere.
 fn reveal(path: &str) -> Result<(), String> {
     reveal_command(path).spawn().map(|_| ()).map_err(|e| format!("can't show {path}: {e}"))
@@ -228,25 +266,31 @@ fn write_file(path: &str, bytes: &[u8]) -> Result<(), String> {
     fileio::write_atomic(std::path::Path::new(path), bytes).map_err(|e| e.to_string())
 }
 
-fn services() -> Services {
+/// Linux: show the dialog for `request` over `parent` on a thread of its own, answering on the
+/// receiver. Shown on the UI thread, nothing would answer the compositor meanwhile, which then
+/// offers to kill the window as not responding (#592).
+fn start_pick(request: PickRequest, parent: &Parent) -> Option<std::sync::mpsc::Receiver<Vec<String>>> {
+    let dialog = file_dialog(&request, parent);
+    let (tx, rx) = std::sync::mpsc::channel();
+    std::thread::Builder::new()
+        .name("file-dialog".into())
+        .spawn(move || {
+            // The app gone meanwhile has no use for the answer.
+            let _ = tx.send(show_dialog(dialog, &request));
+        })
+        .ok()?;
+    Some(rx)
+}
+
+fn services(parent: Parent) -> Services {
+    let (p1, p2, p3, p4, p5) = (parent.clone(), parent.clone(), parent.clone(), parent.clone(), parent);
     Services {
-        pick_open: Some(Box::new(|pick: &FilePick| file_dialog(pick).pick_file().map(|p| p.to_string_lossy().to_string()))),
-        pick_open_multi: Some(Box::new(|| {
-            fileio::place_filters()
-                .fold(rfd::FileDialog::new().set_title("Place"), |d, (name, exts)| d.add_filter(name, exts))
-                .pick_files()
-                .unwrap_or_default()
-                .into_iter()
-                .map(|p| p.to_string_lossy().to_string())
-                .collect()
-        })),
-        pick_save: Some(Box::new(|pick: &FilePick| {
-            // The Templates folder may not exist yet.
-            if let Some(folder) = &pick.folder {
-                let _ = std::fs::create_dir_all(folder);
-            }
-            file_dialog(pick).save_file().map(|p| p.to_string_lossy().to_string())
-        })),
+        pick_open: Some(Box::new(move |pick: &FilePick| pick_now(PickRequest::Open(pick.clone()), &p1).into_iter().next())),
+        pick_open_multi: Some(Box::new(move || pick_now(PickRequest::OpenMany, &p2))),
+        pick_save: Some(Box::new(move |pick: &FilePick| pick_now(PickRequest::Save(pick.clone()), &p3).into_iter().next())),
+        // Windows and macOS dialogs run the window's events while they are open; Linux's don't.
+        start_pick: cfg!(all(unix, not(target_os = "macos")))
+            .then(|| Box::new(move |request: PickRequest| start_pick(request, &p5)) as vectorcraft_ui_egui::picks::StartPick),
         read: Some(Box::new(|p: &str| std::fs::read(p).map_err(|e| e.to_string()))),
         write: Some(Box::new(write_file)),
         // Background Save and Export write from a worker thread.
@@ -264,7 +308,7 @@ fn services() -> Services {
         reveal: Some(Box::new(reveal)),
         // Links panel: Edit Original; Package: Show Package. Relink to Folder and Package pick folders.
         open_file: Some(Box::new(open_file)),
-        pick_folder: Some(Box::new(|| rfd::FileDialog::new().pick_folder().map(|p| p.to_string_lossy().to_string()))),
+        pick_folder: Some(Box::new(move || pick_now(PickRequest::Folder, &p4).into_iter().next())),
         // File → Print: the system's printers and print queue.
         print: Some(Box::new(printing::SystemPrint)),
         ..Default::default()
@@ -314,6 +358,9 @@ fn main() -> std::process::ExitCode {
     // First, so every start-up warning is recorded (`logging`).
     let logger = logging::install();
     vectorcraft_ui_egui::i18n::detect_system_lang_in_background();
+    // Before the first font scan (the app's start): the fonts font services load (#579).
+    #[cfg(all(windows, not(target_vendor = "win7")))]
+    system_fonts::install();
     let mut control_port: Option<u16> = std::env::var("VECTORCRAFT_CONTROL_PORT").ok().and_then(|p| p.parse().ok());
     let mut files = Vec::new();
     let mut in_window_menus = std::env::var_os("VECTORCRAFT_IN_WINDOW_MENUS").is_some_and(|v| !v.is_empty() && v != "0");
@@ -392,7 +439,7 @@ fn main() -> std::process::ExitCode {
             "VectorCraft",
             options,
             Box::new(move |cc| {
-                let mut app = VectorcraftApp::new(Session::new(), services());
+                let mut app = VectorcraftApp::new(Session::new(), services(cc.winit_window().cloned()));
                 load_prefs(&mut app, saved);
                 // Fit the window to its monitor, or put it back where it was (still hidden).
                 if let Some(w) = cc.winit_window() {

apps/vectorcraft/src/system_fonts.rs

@@ -0,0 +1,91 @@
+//! Windows: the font files in DirectWrite's system font collection, scanned with the font folders
+//! (`vectorcraft_text::set_platform_font_files`).
+//!
+//! Font services such as Adobe Fonts load their fonts with GDI at run time, from files in their
+//! own folders, without installing them: the font folders and the registry don't list them. Since
+//! Windows 10 (version 1607) DirectWrite's system font collection holds them too
+//! (<https://learn.microsoft.com/windows/win32/directwrite/what-s-new-in-directwrite-for-windows-8-consumer-preview>,
+//! "Support for Adobe Typekit and other font-service clients"), so VectorCraft lists them as other
+//! apps do, reading the files in place (#579).
+//!
+//! DirectWrite is COM, which has no safe API, hence the scoped `unsafe_code` allowance.
+#![allow(unsafe_code)]
+
+use std::collections::BTreeSet;
+
+use windows::Win32::Graphics::DirectWrite::{
+    DWRITE_FACTORY_TYPE_SHARED, DWriteCreateFactory, IDWriteFactory3, IDWriteFontSet, IDWriteLocalFontFileLoader,
+};
+use windows::core::Interface;
+
+/// The most fonts read from the collection (a system has a few thousand).
+const MAX_FONTS: u32 = 1 << 16;
+/// The longest file path taken, in UTF-16 units (Windows' own limit).
+const MAX_PATH: u32 = 32_767;
+
+/// Have the font scans read the font files DirectWrite lists.
+pub fn install() {
+    vectorcraft_text::set_platform_font_files(font_files);
+}
+
+/// The local files of the fonts in DirectWrite's system font collection as it is now (fonts
+/// loaded since the last call included). None before Windows 10, or when DirectWrite fails: the
+/// font folders and the registry still list the installed fonts.
+fn font_files() -> Vec<String> {
+    match collection_files() {
+        Ok(files) => files.into_iter().collect(),
+        Err(e) => {
+            log::debug!("DirectWrite's system fonts aren't listed: {e}");
+            Vec::new()
+        }
+    }
+}
+
+fn collection_files() -> windows::core::Result<BTreeSet<String>> {
+    // SAFETY: plain DirectWrite calls on interfaces it returned, each checked for failure; the
+    // collection is asked to check for fonts loaded since the factory last looked.
+    let set = unsafe {
+        let factory: IDWriteFactory3 = DWriteCreateFactory(DWRITE_FACTORY_TYPE_SHARED)?;
+        let mut collection = None;
+        factory.GetSystemFontCollection(false, &mut collection, true)?;
+        let Some(collection) = collection else { return Ok(BTreeSet::new()) };
+        collection.GetFontSet()?
+    };
+    // SAFETY: a count of the set's fonts.
+    let count = unsafe { set.GetFontCount() }.min(MAX_FONTS);
+    // Faces of one file (a collection's, a variable font's instances) name it once.
+    Ok((0..count).filter_map(|i| local_path(&set, i)).collect())
+}
+
+/// The path of the file holding font `i` of `set`, when it is a local file (not a downloadable
+/// font, nor one in memory).
+fn local_path(set: &IDWriteFontSet, i: u32) -> Option<String> {
+    // SAFETY: `i` is below the set's count; the key DirectWrite hands back stays valid while
+    // `file` (which owns it) lives, and is passed back with its own size; the path buffer is
+    // sized from DirectWrite's answer plus the terminating NUL.
+    unsafe {
+        let file = set.GetFontFaceReference(i).ok()?.GetFontFile().ok()?;
+        let loader: IDWriteLocalFontFileLoader = file.GetLoader().ok()?.cast().ok()?;
+        let (mut key, mut size) = (std::ptr::null_mut(), 0u32);
+        file.GetReferenceKey(&mut key, &mut size).ok()?;
+        let len = loader.GetFilePathLengthFromKey(key, size).ok()?;
+        if len == 0 || len > MAX_PATH {
+            return None;
+        }
+        let mut path = vec![0u16; len as usize + 1];
+        loader.GetFilePathFromKey(key, size, &mut path).ok()?;
+        Some(String::from_utf16_lossy(path.get(..len as usize)?))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    /// DirectWrite lists the installed fonts, by their files' full paths.
+    #[test]
+    fn directwrite_lists_the_installed_font_files() {
+        let files = super::font_files();
+        assert!(files.iter().all(|f| std::path::Path::new(f).is_absolute()), "{:?}", files.first());
+        let fonts = std::path::Path::new(&std::env::var("WINDIR").unwrap()).join("Fonts").to_string_lossy().to_lowercase();
+        assert!(files.iter().any(|f| f.to_lowercase().starts_with(&fonts)), "{} files, {:?}", files.len(), files.first());
+    }
+}

crates/text/src/fontdb.rs

@@ -782,8 +782,29 @@ pub(crate) fn sfnt_of(tables: &[(&[u8; 4], &[u8])]) -> Option<Vec<u8>> {
     Some(font)
 }
 
-/// The platform's font folders (the system's and the user's) and, on Windows, the font files
-/// registered with it outside them, scanned by [`FontDb::global`].
+/// Lists the font files the platform's font service knows, for [`set_platform_font_files`].
+pub type PlatformFontFiles = fn() -> Vec<String>;
+
+/// What lists the platform's font files, set by the app ([`set_platform_font_files`]).
+#[cfg(not(target_arch = "wasm32"))]
+static PLATFORM_FONT_FILES: std::sync::OnceLock<PlatformFontFiles> = std::sync::OnceLock::new();
+
+/// Have [`system_font_dirs`] add the font files `list` gives (full paths) outside the font
+/// folders, asked again by each scan and each check for installed fonts
+/// ([`FontDb::installed_fonts_changed`]). The desktop app lists DirectWrite's system font
+/// collection on Windows: fonts a font service such as Adobe Fonts loads in place, from files
+/// outside the font folders and unknown to the registry (#579). Only the first call counts.
+pub fn set_platform_font_files(list: PlatformFontFiles) {
+    #[cfg(not(target_arch = "wasm32"))]
+    // A second call keeps the first lister, as documented.
+    let _ = PLATFORM_FONT_FILES.set(list);
+    #[cfg(target_arch = "wasm32")]
+    let _ = list;
+}
+
+/// The platform's font folders (the system's and the user's) and the font files known to it
+/// outside them (on Windows those registered with it, and those [`set_platform_font_files`]
+/// lists), scanned by [`FontDb::global`].
 pub fn system_font_dirs() -> Vec<PathBuf> {
     let mut dirs: Vec<PathBuf> = Vec::new();
     if cfg!(target_arch = "wasm32") {
@@ -824,6 +845,11 @@ pub fn system_font_dirs() -> Vec<PathBuf> {
         // In a Flatpak sandbox, the host's fonts (system, local and the user's).
         dirs.extend(["/run/host/fonts", "/run/host/local-fonts", "/run/host/user-fonts"].map(Into::into));
     }
+    #[cfg(not(target_arch = "wasm32"))]
+    if let Some(list) = PLATFORM_FONT_FILES.get() {
+        let files = fonts_outside(list(), &dirs);
+        dirs.extend(files);
+    }
     dirs
 }
 
@@ -848,7 +874,7 @@ fn registered_font_files(font_dirs: &[PathBuf]) -> Vec<PathBuf> {
 /// The full paths among `registered` (font registrations' data) that aren't in `font_dirs`
 /// (ignoring case, as Windows paths do), sorted and deduplicated. File names alone are files in
 /// the Windows font folder, which is scanned anyway. The count is capped.
-#[cfg(any(windows, test))]
+#[cfg(not(target_arch = "wasm32"))]
 pub(crate) fn fonts_outside(registered: impl IntoIterator<Item = String>, font_dirs: &[PathBuf]) -> Vec<PathBuf> {
     const MAX_REGISTERED: usize = 1 << 16;
     let lower = |p: &Path| PathBuf::from(p.to_string_lossy().to_lowercase());
@@ -1154,6 +1180,7 @@ impl FontDb {
         let mut n = 0;
         let paths = self.font_paths.get();
         let mut modified_at = Vec::new();
+        // Each file with whether it was named by itself rather than found in a folder.
         let mut files = Vec::new();
         let mut stack = paths.clone();
         // Each folder once, however links lead back to it.
@@ -1166,7 +1193,7 @@ impl FontDb {
             modified_at.push((d.clone(), modified(&d)));
             // Not a folder: a font file named by itself (or nothing, yet).
             let Ok(rd) = std::fs::read_dir(&d) else {
-                files.push(d);
+                files.push((d, true));
                 continue;
             };
             for e in rd.flatten() {
@@ -1174,13 +1201,15 @@ impl FontDb {
                 if p.is_dir() {
                     stack.push(p);
                 } else {
-                    files.push(p);
+                    files.push((p, false));
                 }
             }
         }
-        for p in files {
+        for (p, named) in files {
+            // A file named by itself is a font whatever its name (font services keep fonts in
+            // files without an extension); one of a folder's only with a font's extension.
             let ext = p.extension().and_then(|e| e.to_str()).map(|e| e.to_ascii_lowercase());
-            if !matches!(ext.as_deref(), Some("ttf" | "otf" | "ttc" | "otc")) {
+            if !named && !matches!(ext.as_deref(), Some("ttf" | "otf" | "ttc" | "otc")) {
                 continue;
             }
             for FaceStyle { family, style, keys, weight, italic, traits, .. } in file_face_names(&p) {

crates/text/src/lib.rs

@@ -24,7 +24,9 @@ pub mod thread;
 
 pub use craft_fonts::{CRAFT_FONTS, CraftFont};
 pub use features::{LIGATURE_TRACKING_LIMITS, OtFeatures, explicit_ligatures, ligatures_suppressed_by};
-pub use fontdb::{FALLBACK_FAMILY, FontClass, FontDb, FontFace, FontMatch, FontTraits, style_weight, system_font_dirs};
+pub use fontdb::{
+    FALLBACK_FAMILY, FontClass, FontDb, FontFace, FontMatch, FontTraits, PlatformFontFiles, set_platform_font_files, style_weight, system_font_dirs,
+};
 use kurbo::{Affine, BezPath, Point, Rect, Vec2};
 pub use layout::{layout, layout_with};
 pub use vectorcraft_doc::TextObject;

crates/text/src/tests_sysfonts.rs

@@ -237,3 +237,29 @@ fn the_database_tells_when_fonts_were_installed_or_removed_since_its_scan() {
     assert_eq!(db.load_system_fonts(), 2);
     assert_eq!(db.styles(FAMILY), ["Bold"]);
 }
+
+/// A font a font service loads from a file without an extension, outside the font folders.
+fn service_font() -> PathBuf {
+    std::env::temp_dir().join(format!("vc-sysfonts-{}-service", std::process::id())).join(".29457")
+}
+
+/// The fonts a font service (Adobe Fonts on Windows, through DirectWrite) loads in place are
+/// cataloged: named by the platform's lister, read whatever their file is called (#579).
+#[test]
+fn fonts_the_platform_lists_outside_the_font_folders_are_cataloged() {
+    let file = service_font();
+    std::fs::create_dir_all(file.parent().unwrap()).unwrap();
+    std::fs::write(&file, renamed_to("SourceSans3-Regular.ttf", "Service Sans3")).unwrap();
+    // The lister's files outside the font folders are scanned with them, each once (a collection
+    // lists its file once per face).
+    fn lister() -> Vec<String> {
+        vec![service_font().to_string_lossy().into_owned(); 2]
+    }
+    set_platform_font_files(lister);
+    let dirs = system_font_dirs();
+    assert_eq!(dirs.iter().filter(|d| **d == file).count(), 1, "{dirs:?}");
+    // A file named by itself is read without a font's extension, one in a folder isn't.
+    let db = FontDb::with_font_dirs(vec![file.clone()]);
+    assert_eq!(db.styles("Service Sans3"), ["Regular"]);
+    assert!(!FontDb::with_font_dirs(vec![file.parent().unwrap().to_path_buf()]).has_family("Service Sans3"));
+}

crates/ui-egui/src/dialogs/export_for_screens.rs

@@ -424,11 +424,8 @@ fn destination(app: &mut VectorcraftApp, ui: &mut egui::Ui, d: &mut Dialog) {
         let pick = app.services.pick_folder.is_some();
         ui.horizontal(|ui| {
             form::text(ui, d, "folder", if pick { 300.0 } else { 334.0 });
-            if pick
-                && widgets::icon_button(ui, "folder-open", tl!("Choose a folder"), false, 26.0).clicked()
-                && let Some(f) = app.services.pick_folder.as_mut().and_then(|pick| pick())
-            {
-                d.fields.insert("folder".into(), json!(f));
+            if pick && widgets::icon_button(ui, "folder-open", tl!("Choose a folder"), false, 26.0).clicked() {
+                crate::picks::folder_field(app, d, "folder");
             }
         });
         form::check(ui, d, "openLocation", tl!("Open Location after Export"));

crates/ui-egui/src/dialogs/flattener_presets.rs

@@ -145,10 +145,17 @@ fn body(app: &mut VectorcraftApp, ui: &mut egui::Ui, d: &mut Dialog) -> bool {
             }
         }
     }
-    if let Some(a) = act
-        && let Err(e) = run(app, d, a, &preset.name)
-    {
-        app.status(e);
+    if let Some(a) = act {
+        let r = if matches!(a, Action::Import) {
+            // Its file dialog, shown off the UI thread, imports into the dialog as it is then.
+            let current = preset.name.clone();
+            crate::picks::in_dialog(app, d, move |app, d| run(app, d, Action::Import, &current))
+        } else {
+            run(app, d, a, &preset.name)
+        };
+        if let Err(e) = r {
+            app.status(e);
+        }
     }
     false
 }
@@ -181,7 +188,7 @@ fn run(app: &mut VectorcraftApp, d: &mut Dialog, act: Action, current: &str) ->
                 return Ok(());
             }
             let pick = crate::FilePick { filters: vec![("Flattener presets", PRESET_EXTS)], ..Default::default() };
-            let path = app.services.pick_open.as_mut().and_then(|f| f(&pick)).ok_or("cancelled")?;
+            let path = crate::picks::open(app, &pick).ok_or("cancelled")?;
             let r = app.run("flattener.presets.import", json!({ "path": path }))?;
             if let Some(first) = r["imported"].get(0).and_then(Value::as_str) {
                 select(d, first);

crates/ui-egui/src/dialogs/missing_links.rs

@@ -122,7 +122,7 @@ fn confirm(app: &mut VectorcraftApp, d: &Dialog) -> Result<Value, String> {
             p if !p.is_empty() => p,
             _ => {
                 let pick = crate::FilePick { filters: vectorcraft_engine::cmd::fileio::place_filters().collect(), ..Default::default() };
-                app.services.pick_open.as_mut().and_then(|f| f(&pick)).ok_or("cancelled")?
+                crate::picks::open(app, &pick).ok_or("cancelled")?
             }
         };
         out = app.run("links.relink", json!({ "ids": current["ids"], "path": path }))?;

crates/ui-egui/src/dialogs/mod.rs

@@ -315,7 +315,8 @@ pub fn cancel(app: &mut VectorcraftApp) {
 /// Apply the open dialog (OK).
 pub fn confirm(app: &mut VectorcraftApp) -> DialogResult {
     let Some(d) = app.ui.dialog.clone() else { return Err("no dialog open".into()) };
-    (spec(&d.kind).confirm)(app, &d)
+    // A file dialog it shows off the UI thread confirms the dialog as it is again.
+    crate::picks::as_entry(app, || crate::picks::Entry::Confirm(Box::new(d.clone())), |app| (spec(&d.kind).confirm)(app, &d))
 }
 
 pub fn show(app: &mut VectorcraftApp, ctx: &egui::Context) {

crates/ui-egui/src/dialogs/package.rs

@@ -70,11 +70,8 @@ fn body(app: &mut VectorcraftApp, ui: &mut egui::Ui, d: &mut Dialog) -> bool {
     if !downloads(app) {
         widgets::label_row(ui, tl!("Location:"), LABEL, |ui| {
             form::text(ui, d, "folder", 230.0);
-            if let Some(pick) = app.services.pick_folder.as_mut()
-                && ui.button(tl!("Choose…")).clicked()
-                && let Some(f) = pick()
-            {
-                d.fields.insert("folder".into(), json!(f));
+            if app.services.pick_folder.is_some() && ui.button(tl!("Choose…")).clicked() {
+                crate::picks::folder_field(app, d, "folder");
             }
         });
         ui.add_space(4.0);

crates/ui-egui/src/dialogs/pdf_presets.rs

@@ -102,10 +102,17 @@ fn body(app: &mut VectorcraftApp, ui: &mut egui::Ui, d: &mut Dialog) -> bool {
             details(ui, &t, preset, builtin);
         });
     });
-    if let Some(a) = act
-        && let Err(e) = run(app, d, a, &preset.name)
-    {
-        app.status(e);
+    if let Some(a) = act {
+        let r = if matches!(a, Action::Import) {
+            // Its file dialog, shown off the UI thread, imports into the dialog as it is then.
+            let current = preset.name.clone();
+            crate::picks::in_dialog(app, d, move |app, d| run(app, d, Action::Import, &current))
+        } else {
+            run(app, d, a, &preset.name)
+        };
+        if let Err(e) = r {
+            app.status(e);
+        }
     }
     false
 }
@@ -169,7 +176,7 @@ fn run(app: &mut VectorcraftApp, d: &mut Dialog, act: Action, current: &str) ->
                 return Ok(());
             }
             let pick = crate::FilePick { filters: vec![("PDF presets", vectorcraft_engine::cmd::pdfcmds::PRESET_EXTS)], ..Default::default() };
-            let path = app.services.pick_open.as_mut().and_then(|f| f(&pick)).ok_or("cancelled")?;
+            let path = crate::picks::open(app, &pick).ok_or("cancelled")?;
             let r = app.run("pdf.preset.import", json!({ "path": path }))?;
             if let Some(first) = r["imported"].get(0).and_then(Value::as_str) {
                 select(d, first);

crates/ui-egui/src/dialogs/perspective_presets.rs

@@ -150,10 +150,17 @@ fn body(app: &mut VectorcraftApp, ui: &mut egui::Ui, d: &mut Dialog) -> bool {
         });
     });
     let name = preset.name.clone();
-    if let Some(a) = act
-        && let Err(e) = run(app, d, a, &name)
-    {
-        app.status(e);
+    if let Some(a) = act {
+        let r = if matches!(a, Action::Import) {
+            // Its file dialog, shown off the UI thread, imports into the dialog as it is then.
+            let current = name.clone();
+            crate::picks::in_dialog(app, d, move |app, d| run(app, d, Action::Import, &current))
+        } else {
+            run(app, d, a, &name)
+        };
+        if let Err(e) = r {
+            app.status(e);
+        }
     }
     false
 }
@@ -187,7 +194,7 @@ pub(super) fn run(app: &mut VectorcraftApp, d: &mut Dialog, act: Action, current
                 return Ok(());
             }
             let pick = crate::FilePick { filters: vec![("Perspective grid presets", PRESET_EXTS)], ..Default::default() };
-            let path = app.services.pick_open.as_mut().and_then(|f| f(&pick)).ok_or("cancelled")?;
+            let path = crate::picks::open(app, &pick).ok_or("cancelled")?;
             let r = app.run("perspective.presets.import", json!({ "path": path }))?;
             if let Some(first) = r["imported"].get(0).and_then(Value::as_str) {
                 select(d, first);

crates/ui-egui/src/dialogs/print_presets.rs

@@ -111,10 +111,17 @@ fn body(app: &mut VectorcraftApp, ui: &mut egui::Ui, d: &mut Dialog) -> bool {
             }
         });
     });
-    if let Some(a) = act
-        && let Err(e) = run(app, d, a, &name)
-    {
-        app.status(e);
+    if let Some(a) = act {
+        let r = if matches!(a, Action::Import) {
+            // Its file dialog, shown off the UI thread, imports into the dialog as it is then.
+            let current = name.clone();
+            crate::picks::in_dialog(app, d, move |app, d| run(app, d, Action::Import, &current))
+        } else {
+            run(app, d, a, &name)
+        };
+        if let Err(e) = r {
+            app.status(e);
+        }
     }
     false
 }
@@ -149,7 +156,7 @@ pub(super) fn run(app: &mut VectorcraftApp, d: &mut Dialog, act: Action, current
                 return Ok(());
             }
             let pick = crate::FilePick { filters: vec![("Print presets", PRESET_EXTS)], ..Default::default() };
-            let path = app.services.pick_open.as_mut().and_then(|f| f(&pick)).ok_or("cancelled")?;
+            let path = crate::picks::open(app, &pick).ok_or("cancelled")?;
             let r = app.run("print.presets.import", json!({ "path": path }))?;
             if let Some(first) = r["imported"].get(0).and_then(Value::as_str) {
                 select(d, first);

crates/ui-egui/src/i18n/cs.tsv

@@ -634,3 +634,4 @@
 	Clipboard Handling	Práce se schránkou
 	Appearance of Black	Vzhled černé
 	Devices	Zařízení
+	A file dialog is open: choose there first	Je otevřené dialogové okno souboru: nejprve vyberte v něm

crates/ui-egui/src/i18n/es.tsv

@@ -3598,3 +3598,4 @@ axis	Both	Ambos
 	Off: an editable copy of its art, embedded in this document.	Desactivado: una copia editable de su ilustración, incrustada en este documento.
 	Images: link to the file instead of only embedding it.	Imágenes: vincular al archivo en lugar de solo incrustarlo.
 	VectorCraft documents: one locked object, updated when the file changes.	Documentos de VectorCraft: un objeto bloqueado que se actualiza cuando cambia el archivo.
+	A file dialog is open: choose there first	Hay un cuadro de diálogo de archivos abierto: elija primero en él

crates/ui-egui/src/i18n/it.tsv

@@ -3598,3 +3598,4 @@ axis	Both	Entrambi
 	Off: an editable copy of its art, embedded in this document.	Disattivato: una copia modificabile della sua grafica, incorporata in questo documento.
 	Images: link to the file instead of only embedding it.	Immagini: collega il file invece di incorporarlo soltanto.
 	VectorCraft documents: one locked object, updated when the file changes.	Documenti VectorCraft: un unico oggetto bloccato, aggiornato quando il file cambia.
+	A file dialog is open: choose there first	È aperta una finestra di dialogo dei file: scegli prima lì

crates/ui-egui/src/i18n/ja.tsv

@@ -3060,3 +3060,4 @@ theme	Appearance	外観
 	Off: an editable copy of its art, embedded in this document.	オフ：アートの編集可能なコピーをこのドキュメントに埋め込みます。
 	Images: link to the file instead of only embedding it.	画像：埋め込むだけでなく、ファイルにリンクします。
 	VectorCraft documents: one locked object, updated when the file changes.	VectorCraft ドキュメント：ロックされた 1 つのオブジェクト。ファイルの変更時に更新されます。
+	A file dialog is open: choose there first	ファイルダイアログが開いています。先にそちらで選択してください

crates/ui-egui/src/i18n/pt-br.tsv

@@ -2648,3 +2648,4 @@
 	Off: an editable copy of its art, embedded in this document.	Desativado: uma cópia editável da arte, incorporada neste documento.
 	Images: link to the file instead of only embedding it.	Imagens: vincular ao arquivo em vez de apenas incorporá-lo.
 	VectorCraft documents: one locked object, updated when the file changes.	Documentos do VectorCraft: um objeto bloqueado, atualizado quando o arquivo muda.
+	A file dialog is open: choose there first	Há uma caixa de diálogo de arquivos aberta: escolha nela primeiro

crates/ui-egui/src/i18n/ru.tsv

@@ -3596,3 +3596,4 @@ axis	Both	Оба
 	Off: an editable copy of its art, embedded in this document.	Выкл.: редактируемая копия его рисунка, внедрённая в этот документ.
 	Images: link to the file instead of only embedding it.	Изображения: связывать с файлом вместо простого внедрения.
 	VectorCraft documents: one locked object, updated when the file changes.	Документы VectorCraft: один заблокированный объект, обновляемый при изменении файла.
+	A file dialog is open: choose there first	Открыто окно выбора файла: сначала сделайте выбор в нём

crates/ui-egui/src/i18n/zh-hans.tsv

@@ -3315,3 +3315,4 @@ axis	Both	两者
 	Off: an editable copy of its art, embedded in this document.	关闭：将其图稿的可编辑副本嵌入此文档。
 	Images: link to the file instead of only embedding it.	图像：链接到文件，而不只是嵌入。
 	VectorCraft documents: one locked object, updated when the file changes.	VectorCraft 文档：一个锁定对象，文件更改时随之更新。
+	A file dialog is open: choose there first	文件对话框已打开：请先在其中选择

crates/ui-egui/src/i18n/zh-hant.tsv

@@ -3090,3 +3090,4 @@ axis	Both	兩者
 	Off: an editable copy of its art, embedded in this document.	關閉：將其圖稿的可編輯副本內嵌在此文件中。
 	Images: link to the file instead of only embedding it.	影像：連結至檔案，而不只是嵌入。
 	VectorCraft documents: one locked object, updated when the file changes.	VectorCraft 文件：單一鎖定物件，檔案變更時隨之更新。
+	A file dialog is open: choose there first	檔案對話方塊已開啟：請先在其中選擇

crates/ui-egui/src/io.rs

@@ -72,7 +72,7 @@ pub fn open_document(app: &mut VectorcraftApp, name: &str, bytes: &[u8], path: O
 
 /// A path from the open dialog, or "cancelled".
 fn pick_open(app: &mut VectorcraftApp, pick: &FilePick) -> Result<String, String> {
-    app.services.pick_open.as_mut().and_then(|f| f(pick)).ok_or_else(|| "cancelled".into())
+    crate::picks::open(app, pick).ok_or_else(|| "cancelled".into())
 }
 
 /// Object › Plug-ins › Install Plug-in…: installs the `.wasm` at `path`, else a picked one (the
@@ -164,7 +164,7 @@ fn pick_path(app: &mut VectorcraftApp, pick: &FilePick) -> Result<String, String
     if is_web(app) {
         return Ok(pick.name.clone());
     }
-    let picked = app.services.pick_save.as_mut().and_then(|f| f(pick)).ok_or("cancelled")?;
+    let picked = crate::picks::save(app, pick).ok_or("cancelled")?;
     Ok(with_extension(&picked, &fileio::extension(&pick.name), |_| true))
 }
 

crates/ui-egui/src/lib.rs

@@ -36,6 +36,7 @@ pub mod menus;
 pub mod native_menu;
 pub mod palette;
 pub mod panels;
+pub mod picks;
 pub mod place;
 pub mod prefs_dialog;
 pub mod print;
@@ -95,6 +96,8 @@ mod tests_pathtype;
 #[cfg(test)]
 mod tests_pdfoutput;
 #[cfg(test)]
+mod tests_picks;
+#[cfg(test)]
 mod tests_place;
 #[cfg(test)]
 mod tests_plugins;
@@ -233,6 +236,10 @@ pub struct Services {
     pub print: Option<Box<dyn print::PrintService>>,
     /// The macOS menu bar, when the desktop app installed one: the in-window menus are hidden then.
     pub native_menu: Option<native_menu::NativeMenu>,
+    /// Show file dialogs off the UI thread (desktop Linux, where a dialog in line holds the window
+    /// and the compositor finds it not answering): what asked runs again with the answer
+    /// ([`picks`]). Without it they are shown in line.
+    pub start_pick: Option<picks::StartPick>,
 }
 
 /// Cached canvas raster.
@@ -347,6 +354,11 @@ pub struct VectorcraftApp {
     /// The thread that checks the system clipboard for `system_paste` instead
     /// ([`Services::clipboard_probe`]).
     clipboard_probe: Option<clipboard_probe::Probe>,
+    /// File dialogs shown off the UI thread and what runs again with their answers.
+    pub(crate) picks: picks::Picks,
+    /// The look for fonts installed or removed while the app was in the background, running
+    /// ([`Self::refresh_installed_fonts`]): whether they were.
+    font_check: Option<std::sync::mpsc::Receiver<bool>>,
     /// Keyboard pastes of something other than text (see [`shortcuts::PasteChord`]).
     pub(crate) paste_chord: shortcuts::PasteChord,
     /// Saves and exports running in the background (Preferences → File Handling).
@@ -423,6 +435,8 @@ impl VectorcraftApp {
             system_paste: false,
             system_paste_at: f64::NEG_INFINITY,
             clipboard_probe: None,
+            picks: picks::Picks::default(),
+            font_check: None,
             paste_chord: Default::default(),
             background: Default::default(),
             recovery: Default::default(),
@@ -485,6 +499,16 @@ impl VectorcraftApp {
 
     /// Run a UI or engine command by id. The single entry point for every frontend path.
     pub fn run(&mut self, id: &str, params: Value) -> Result<Value, String> {
+        // A file dialog it shows off the UI thread runs it again with the path picked.
+        if self.picks.is_entry_free() {
+            let entry = picks::Entry::Command(id.to_string(), params.clone());
+            return picks::as_entry(self, move || entry, |app| app.run_now(id, params));
+        }
+        self.run_now(id, params)
+    }
+
+    /// [`Self::run`] it, inside what asks for file dialogs.
+    fn run_now(&mut self, id: &str, params: Value) -> Result<Value, String> {
         self.run_count = self.run_count.wrapping_add(1);
         if let Some(r) = menus::run_ui_command(self, id, &params) {
             return r;
@@ -785,6 +809,8 @@ impl VectorcraftApp {
             self.system_paste_at = now;
             self.system_paste = wanted && self.system_clipboard_pasteable();
         }
+        self.poll_font_check(ctx);
+        picks::poll(self, ctx);
         background::poll(self);
         if !self.background.jobs.is_empty() {
             // Keep the status bar's progress moving and pick the result up when it arrives.
@@ -858,10 +884,38 @@ impl VectorcraftApp {
 
     /// Fonts installed or removed while the app was in the background are listed when it comes
     /// back (Refresh Font List by itself): a look at the font folders, a scan only when they changed.
+    /// The look runs on another thread (asking DirectWrite for the fonts font services loaded
+    /// meanwhile takes tens of milliseconds on Windows, #579), [`Self::poll_font_check`] scans.
     fn refresh_installed_fonts(&mut self) {
-        if vectorcraft_text::FontDb::global().installed_fonts_changed() {
-            // A failure shows in the status bar, as the menu item's does.
-            let _ = self.run("text.rescanFonts", json!({}));
+        if self.font_check.is_some() {
+            return;
+        }
+        let (tx, rx) = std::sync::mpsc::channel();
+        let look = move || {
+            // The UI gone meanwhile has nothing to refresh.
+            let _ = tx.send(vectorcraft_text::FontDb::global().installed_fonts_changed());
+        };
+        let spawned =
+            if cfg!(target_arch = "wasm32") { None } else { std::thread::Builder::new().name("font-check".into()).spawn(look.clone()).ok() };
+        if spawned.is_none() {
+            look();
+        }
+        self.font_check = Some(rx);
+    }
+
+    /// Rescan the fonts once [`Self::refresh_installed_fonts`]'s look says they changed.
+    fn poll_font_check(&mut self, ctx: &egui::Context) {
+        let Some(check) = &self.font_check else { return };
+        match check.try_recv() {
+            Ok(changed) => {
+                self.font_check = None;
+                if changed {
+                    // A failure shows in the status bar, as the menu item's does.
+                    let _ = self.run("text.rescanFonts", json!({}));
+                }
+            }
+            Err(std::sync::mpsc::TryRecvError::Empty) => ctx.request_repaint_after(std::time::Duration::from_millis(50)),
+            Err(std::sync::mpsc::TryRecvError::Disconnected) => self.font_check = None,
         }
     }
 

crates/ui-egui/src/panels/asset_export.rs

@@ -185,17 +185,23 @@ fn collect(app: &mut VectorcraftApp, ctx: &egui::Context, ids: Option<Vec<NodeId
 /// folder picker: the last folder Export for Screens used, else the Desktop); the web downloads
 /// them, several as one zip.
 fn export(app: &mut VectorcraftApp, ids: Vec<u64>, files_each: usize) {
+    // The folder picked off the UI thread exports them then.
+    crate::picks::button(app, move |app| export_now(app, ids.clone(), files_each));
+}
+
+fn export_now(app: &mut VectorcraftApp, ids: Vec<u64>, files_each: usize) {
     let mut p = json!({ "assets": ids });
     if io::is_web(app) {
         p["zip"] = json!(ids.len() * files_each > 1);
     } else {
         let saved = app.session.active().map(|st| st.doc.export_settings.clone()).unwrap_or_default();
-        let folder = match app.services.pick_folder.as_mut() {
-            Some(pick) => match pick() {
+        let folder = if crate::picks::can(app, &crate::picks::PickRequest::Folder) {
+            match crate::picks::folder(app) {
                 Some(f) => f,
                 None => return,
-            },
-            None => match saved
+            }
+        } else {
+            match saved
                 .get("folder")
                 .and_then(Value::as_str)
                 .filter(|f| !f.is_empty())
@@ -204,7 +210,7 @@ fn export(app: &mut VectorcraftApp, ids: Vec<u64>, files_each: usize) {
             {
                 Some(f) => f,
                 None => return app.status("choose a folder to export to".to_string()),
-            },
+            }
         };
         p["folder"] = json!(folder);
         p["openLocation"] = json!(saved.get("openLocation").and_then(Value::as_bool).unwrap_or(true));

crates/ui-egui/src/panels/library_panel.rs

@@ -154,7 +154,7 @@ pub(crate) fn pick_library_file(app: &mut VectorcraftApp, path: Option<String>)
     }
     path.or_else(|| {
         let pick = crate::FilePick { filters: vectorcraft_engine::cmd::fileio::open_filters().collect(), ..Default::default() };
-        app.services.pick_open.as_mut().and_then(|f| f(&pick))
+        crate::picks::open(app, &pick)
     })
     .map(Some)
     .ok_or_else(|| "cancelled".into())

crates/ui-egui/src/panels/links.rs

@@ -116,15 +116,23 @@ fn report(app: &mut VectorcraftApp, r: Result<Value, String>, done: impl FnOnce(
 
 /// Relink images `ids` to a picked file.
 pub(crate) fn relink(app: &mut VectorcraftApp, ids: Vec<u64>) {
+    crate::picks::button(app, move |app| relink_picked(app, ids.clone()));
+}
+
+fn relink_picked(app: &mut VectorcraftApp, ids: Vec<u64>) {
     let pick = crate::FilePick { filters: vectorcraft_engine::cmd::fileio::place_filters().collect(), ..Default::default() };
-    let Some(path) = app.services.pick_open.as_mut().and_then(|f| f(&pick)) else { return };
+    let Some(path) = crate::picks::open(app, &pick) else { return };
     let r = app.run("links.relink", json!({ "ids": ids, "path": path }));
     report(app, r, |v| format!("Relinked {} image(s)", v["relinked"].as_array().map_or(0, Vec::len)));
 }
 
 /// Relink images `ids` (none: every missing one) to the files of their names in a picked folder.
 fn relink_to_folder(app: &mut VectorcraftApp, ids: Vec<u64>) {
-    let Some(folder) = app.services.pick_folder.as_mut().and_then(|f| f()) else { return };
+    crate::picks::button(app, move |app| relink_to_picked_folder(app, ids.clone()));
+}
+
+fn relink_to_picked_folder(app: &mut VectorcraftApp, ids: Vec<u64>) {
+    let Some(folder) = crate::picks::folder(app) else { return };
     let ids = Some(ids).filter(|i| !i.is_empty());
     let r = app.run("links.relink", json!({ "ids": ids, "folder": folder }));
     report(app, r, |v| {
@@ -154,9 +162,12 @@ pub(crate) fn unembed(app: &mut VectorcraftApp, id: u64, name: &str) {
         }
         return;
     }
-    let Some(path) = app.services.pick_save.as_mut().and_then(|f| f(&crate::FilePick::named(name))) else { return };
-    let r = app.run("links.unembed", json!({ "id": id, "path": path }));
-    report(app, r, |v| format!("Unembedded to {}", v["path"].as_str().unwrap_or_default()));
+    let name = name.to_string();
+    crate::picks::button(app, move |app| {
+        let Some(path) = crate::picks::save(app, &crate::FilePick::named(&name)) else { return };
+        let r = app.run("links.unembed", json!({ "id": id, "path": path }));
+        report(app, r, |v| format!("Unembedded to {}", v["path"].as_str().unwrap_or_default()));
+    });
 }
 
 /// The UI commands `links.editOriginal` (open the linked file in its app) and `links.reveal`

crates/ui-egui/src/picks.rs

@@ -0,0 +1,237 @@
+//! File dialogs that leave the window running (#592).
+//!
+//! The app asks for a path where it needs one (Open, Save As, Export, Place, Relink, presets…)
+//! and goes on with it at once, so a dialog shown on the UI thread holds the window until it
+//! closes. On Windows and macOS the dialog runs the window's events meanwhile; on Linux nothing
+//! does, so a Wayland compositor finds the window not answering and offers to kill it. There the
+//! host shows dialogs on another thread ([`Services::start_pick`]): asking returns no path for now,
+//! and when the dialog answers, what asked (the command, the dialog's OK, a panel's button: the
+//! *entry*) runs again and gets the picked path at once.
+
+use std::rc::Rc;
+use std::sync::mpsc::{Receiver, TryRecvError};
+
+use serde_json::Value;
+
+use crate::state::Dialog;
+use crate::{FilePick, VectorcraftApp};
+
+/// A file dialog to show.
+#[derive(Clone, Debug, PartialEq)]
+pub enum PickRequest {
+    /// An open dialog for one file.
+    Open(FilePick),
+    /// An open dialog for files to place.
+    OpenMany,
+    /// A save dialog.
+    Save(FilePick),
+    /// A folder picker.
+    Folder,
+}
+
+/// The paths a dialog shown off the UI thread picked (none: cancelled).
+pub type PickAnswer = Vec<String>;
+
+/// Shows a dialog off the UI thread; its answer arrives on the receiver. `None` when it can't, and
+/// the dialog is then shown in line.
+pub type StartPick = Box<dyn FnMut(PickRequest) -> Option<Receiver<PickAnswer>>>;
+
+/// What runs again with the picked path.
+#[derive(Clone)]
+pub(crate) enum Entry {
+    /// A command (`app.run`).
+    Command(String, Value),
+    /// A dialog's OK (`dialogs::confirm`), on the dialog as it was.
+    Confirm(Box<Dialog>),
+    /// A panel's or a dialog's button.
+    Call(Rc<dyn Fn(&mut VectorcraftApp)>),
+}
+
+/// A dialog shown off the UI thread, waiting for its answer.
+struct Waiting {
+    request: PickRequest,
+    answer: Receiver<PickAnswer>,
+    entry: Entry,
+}
+
+/// The app's file dialogs ([`VectorcraftApp`]'s `picks`).
+#[derive(Default)]
+pub(crate) struct Picks {
+    /// What is running now and asks for a path, the outermost one.
+    entry: Option<Entry>,
+    waiting: Option<Waiting>,
+    /// A picked answer for the entry running again: the dialog it asks for gets it.
+    answer: Option<(PickRequest, PickAnswer)>,
+}
+
+impl Picks {
+    /// Nothing asking for file dialogs is running.
+    pub(crate) fn is_entry_free(&self) -> bool {
+        self.entry.is_none()
+    }
+}
+
+/// Run `f` as `entry`: a dialog it asks for off the UI thread runs `entry` again when it
+/// answers. Inside another entry, that one runs again instead.
+pub(crate) fn as_entry<R>(app: &mut VectorcraftApp, entry: impl FnOnce() -> Entry, f: impl FnOnce(&mut VectorcraftApp) -> R) -> R {
+    if app.picks.entry.is_some() {
+        return f(app);
+    }
+    app.picks.entry = Some(entry());
+    let r = f(app);
+    app.picks.entry = None;
+    r
+}
+
+/// [`as_entry`] for a panel's or a dialog's button that `f` handles.
+pub(crate) fn button(app: &mut VectorcraftApp, f: impl Fn(&mut VectorcraftApp) + 'static) {
+    let f = Rc::new(f);
+    let again = f.clone();
+    as_entry(app, move || Entry::Call(again), |app| f(app));
+}
+
+/// A dialog body's action `f` on `d` (the open dialog's copy) that asks for a file dialog: shown
+/// off the UI thread, its answer runs `f` again on the open dialog, when it is still of that kind.
+pub(crate) fn in_dialog(
+    app: &mut VectorcraftApp,
+    d: &mut Dialog,
+    f: impl Fn(&mut VectorcraftApp, &mut Dialog) -> Result<(), String> + 'static,
+) -> Result<(), String> {
+    let f = Rc::new(f);
+    let (again, kind) = (f.clone(), d.kind.clone());
+    let entry = move || {
+        Entry::Call(Rc::new(move |app: &mut VectorcraftApp| {
+            let Some(mut d) = app.ui.dialog.take() else { return };
+            let r = if d.kind == kind { again(app, &mut d) } else { Ok(()) };
+            app.ui.dialog = Some(d);
+            if let Err(e) = r {
+                app.status(e);
+            }
+        }))
+    };
+    as_entry(app, entry, |app| f(app, d))
+}
+
+/// A dialog body's folder button: the folder picked into field `key` of `d` ([`in_dialog`]).
+pub(crate) fn folder_field(app: &mut VectorcraftApp, d: &mut Dialog, key: &'static str) {
+    let r = in_dialog(app, d, move |app, d| {
+        if let Some(f) = folder(app) {
+            d.fields.insert(key.into(), serde_json::json!(f));
+        }
+        Ok(())
+    });
+    // Picking a folder doesn't fail.
+    let _ = r;
+}
+
+/// A path from an open dialog for `pick` (none: cancelled, or shown off the UI thread for now).
+pub(crate) fn open(app: &mut VectorcraftApp, pick: &FilePick) -> Option<String> {
+    ask(app, PickRequest::Open(pick.clone()))?.into_iter().next()
+}
+
+/// A path from a save dialog for `pick`.
+pub(crate) fn save(app: &mut VectorcraftApp, pick: &FilePick) -> Option<String> {
+    ask(app, PickRequest::Save(pick.clone()))?.into_iter().next()
+}
+
+/// A folder from the folder picker.
+pub(crate) fn folder(app: &mut VectorcraftApp) -> Option<String> {
+    ask(app, PickRequest::Folder)?.into_iter().next()
+}
+
+/// Paths from the open dialog for files to place (none: cancelled).
+pub(crate) fn open_many(app: &mut VectorcraftApp) -> Vec<String> {
+    ask(app, PickRequest::OpenMany).unwrap_or_default()
+}
+
+/// Whether the host shows `request`'s kind of dialog at all.
+pub(crate) fn can(app: &VectorcraftApp, request: &PickRequest) -> bool {
+    let s = &app.services;
+    match request {
+        PickRequest::Open(_) => s.pick_open.is_some(),
+        PickRequest::OpenMany => s.pick_open_multi.is_some() || s.pick_open.is_some(),
+        PickRequest::Save(_) => s.pick_save.is_some(),
+        PickRequest::Folder => s.pick_folder.is_some(),
+    }
+}
+
+/// The paths `request`'s dialog picked: the answer kept for it, else shown off the UI thread (no
+/// paths for now), else shown in line.
+fn ask(app: &mut VectorcraftApp, request: PickRequest) -> Option<PickAnswer> {
+    // One for another dialog is dropped: the entry took another way this time.
+    if let Some((asked, answer)) = app.picks.answer.take()
+        && asked == request
+    {
+        return Some(answer);
+    }
+    if !can(app, &request) {
+        return None;
+    }
+    if let (Some(entry), Some(start)) = (app.picks.entry.clone(), app.services.start_pick.as_mut()) {
+        if app.picks.waiting.is_some() {
+            app.status(tl!("A file dialog is open: choose there first"));
+            return None;
+        }
+        if let Some(answer) = start(request.clone()) {
+            app.picks.waiting = Some(Waiting { request, answer, entry });
+            return None;
+        }
+    }
+    let s = &mut app.services;
+    let one = |p: Option<String>| Some(p.into_iter().collect());
+    match &request {
+        PickRequest::Open(pick) => one(s.pick_open.as_mut().and_then(|f| f(pick))),
+        PickRequest::Save(pick) => one(s.pick_save.as_mut().and_then(|f| f(pick))),
+        PickRequest::Folder => one(s.pick_folder.as_mut().and_then(|f| f())),
+        PickRequest::OpenMany => match (s.pick_open_multi.as_mut(), s.pick_open.as_mut()) {
+            (Some(many), _) => Some(many()),
+            (None, Some(f)) => one(f(&FilePick::default())),
+            (None, None) => None,
+        },
+    }
+}
+
+/// Each frame: when the dialog shown off the UI thread answers with paths, run its entry again
+/// with them. While it is open, look again shortly.
+pub(crate) fn poll(app: &mut VectorcraftApp, ctx: &egui::Context) {
+    let Some(w) = &app.picks.waiting else { return };
+    let answer = match w.answer.try_recv() {
+        Ok(answer) => answer,
+        Err(TryRecvError::Empty) => {
+            // What asked gave up for now: no "cancelled" while the dialog is open.
+            if app.ui.status == "cancelled" {
+                app.ui.status.clear();
+            }
+            ctx.request_repaint_after(std::time::Duration::from_millis(100));
+            return;
+        }
+        // The dialog's thread is gone: as cancelled.
+        Err(TryRecvError::Disconnected) => vec![],
+    };
+    let Some(Waiting { request, entry, .. }) = app.picks.waiting.take() else { return };
+    if answer.is_empty() {
+        return;
+    }
+    app.picks.answer = Some((request, answer));
+    rerun(app, entry);
+    // An entry that took another way this time leaves the answer unused.
+    app.picks.answer = None;
+}
+
+/// Run `entry` again.
+fn rerun(app: &mut VectorcraftApp, entry: Entry) {
+    let r = match entry {
+        Entry::Command(id, params) => app.run(&id, params).map(|_| ()),
+        Entry::Confirm(d) => {
+            app.ui.dialog = Some(*d);
+            crate::dialogs::confirm(app).map(|_| ())
+        }
+        Entry::Call(f) => {
+            f(app);
+            Ok(())
+        }
+    };
+    if let Err(e) = r {
+        app.status(e);
+    }
+}

crates/ui-egui/src/place.rs

@@ -135,10 +135,10 @@ fn pick(app: &mut VectorcraftApp) -> Result<(), String> {
         f();
         return Ok(());
     }
-    let paths = match (app.services.pick_open_multi.as_mut(), app.services.pick_open.as_mut()) {
-        (Some(f), _) => f(),
-        (None, Some(f)) => f(&crate::FilePick { filters: fileio::place_filters().collect(), ..Default::default() }).into_iter().collect(),
-        (None, None) => vec![],
+    let paths = if app.services.pick_open_multi.is_some() {
+        crate::picks::open_many(app)
+    } else {
+        crate::picks::open(app, &crate::FilePick { filters: fileio::place_filters().collect(), ..Default::default() }).into_iter().collect()
     };
     if paths.is_empty() {
         return Err("cancelled".into());

crates/ui-egui/src/shortcut_editor.rs

@@ -458,7 +458,7 @@ pub fn run_command(app: &mut VectorcraftApp, id: &str, p: &Value) -> Option<Resu
         "shortcuts.export" => {
             let v = export_json(&app.ui.shortcut_set, &app.ui.shortcut_overrides);
             let bytes = serde_json::to_vec_pretty(&v).unwrap_or_default();
-            let path = s("path").or_else(|| app.services.pick_save.as_mut().and_then(|f| f(&crate::FilePick::named("VectorCraft Shortcuts.json"))));
+            let path = s("path").or_else(|| crate::picks::save(app, &crate::FilePick::named("VectorCraft Shortcuts.json")));
             match path {
                 Some(path) => match app.services.write.as_mut() {
                     Some(w) => w(&path, &bytes).map(|_| json!({"path": path})),
@@ -477,7 +477,7 @@ pub fn run_command(app: &mut VectorcraftApp, id: &str, p: &Value) -> Option<Resu
             let data = if let Some(v) = p.get("data") {
                 Ok(v.clone())
             } else {
-                let path = s("path").or_else(|| app.services.pick_open.as_mut().and_then(|f| f(&crate::FilePick::default())));
+                let path = s("path").or_else(|| crate::picks::open(app, &crate::FilePick::default()));
                 match (path, app.services.read.as_ref()) {
                     (Some(path), Some(r)) => r(&path).and_then(|b| serde_json::from_slice(&b).map_err(|e| e.to_string())),
                     (None, _) => Err("cancelled".into()),

crates/ui-egui/src/tests_picks.rs

@@ -0,0 +1,113 @@
+//! File dialogs shown off the UI thread (Linux, #592): what asked runs again with the answer.
+
+use std::cell::RefCell;
+use std::rc::Rc;
+use std::sync::mpsc::{Sender, channel};
+
+use serde_json::json;
+use vectorcraft_engine::Session;
+
+use crate::picks::{self, PickRequest};
+use crate::state::Dialog;
+use crate::{FilePick, Services, VectorcraftApp};
+
+const SVG: &[u8] = br#"<svg xmlns="http://www.w3.org/2000/svg" width="40" height="30"><rect width="10" height="10"/></svg>"#;
+
+/// A dialog asked for, and where its answer goes.
+type Asked = (PickRequest, Sender<Vec<String>>);
+
+/// The dialogs showing.
+#[derive(Clone, Default)]
+struct Shown(Rc<RefCell<Vec<Asked>>>);
+
+impl Shown {
+    fn requests(&self) -> Vec<PickRequest> {
+        self.0.borrow().iter().map(|(r, _)| r.clone()).collect()
+    }
+    /// The last dialog shown answers `paths`.
+    fn answer(&self, paths: &[&str]) {
+        let (_, tx) = self.0.borrow_mut().pop().expect("a dialog is showing");
+        tx.send(paths.iter().map(|p| p.to_string()).collect()).unwrap();
+    }
+}
+
+/// A desktop app whose dialogs show off the UI thread (none in line), reading [`SVG`] from any path
+/// and writing files to `written`.
+fn app() -> (VectorcraftApp, Shown, Rc<RefCell<Vec<String>>>) {
+    let (shown, written) = (Shown::default(), Rc::new(RefCell::new(vec![])));
+    let (s, w) = (shown.clone(), written.clone());
+    let in_line = |_: &FilePick| -> Option<String> { panic!("no dialog on the UI thread") };
+    let services = Services {
+        pick_open: Some(Box::new(in_line)),
+        pick_save: Some(Box::new(in_line)),
+        pick_folder: Some(Box::new(|| panic!("no dialog on the UI thread"))),
+        read: Some(Box::new(|_: &str| Ok(SVG.to_vec()))),
+        write: Some(Box::new(move |path: &str, _: &[u8]| {
+            w.borrow_mut().push(path.to_string());
+            Ok(())
+        })),
+        start_pick: Some(Box::new(move |request: PickRequest| {
+            let (tx, rx) = channel();
+            s.0.borrow_mut().push((request, tx));
+            Some(rx)
+        })),
+        ..Default::default()
+    };
+    (VectorcraftApp::new(Session::new(), services), shown, written)
+}
+
+fn poll(app: &mut VectorcraftApp) {
+    picks::poll(app, &egui::Context::default());
+}
+
+#[test]
+fn file_open_opens_what_its_dialog_picks_when_it_answers() {
+    let (mut app, shown, _) = app();
+    // The dialog shows; File › Open gives up for now, without a "cancelled".
+    assert!(app.run("file.open", json!({})).is_err());
+    assert!(matches!(shown.requests().as_slice(), [PickRequest::Open(_)]));
+    poll(&mut app);
+    assert!(app.session.documents().is_empty() && app.ui.status.is_empty(), "{}", app.ui.status);
+    // Another dialog waits for this one.
+    assert!(app.run("file.open", json!({})).is_err());
+    assert_eq!(shown.requests().len(), 1);
+    assert!(app.ui.status.contains("file dialog is open"), "{}", app.ui.status);
+    shown.answer(&["/art/a.svg"]);
+    poll(&mut app);
+    assert_eq!(app.session.documents().len(), 1);
+    assert_eq!(app.session.active().and_then(|d| d.path.clone()).as_deref(), Some("/art/a.svg"));
+    // Cancelled: nothing happens, and dialogs show again.
+    assert!(app.run("file.open", json!({})).is_err());
+    shown.answer(&[]);
+    poll(&mut app);
+    assert_eq!(app.session.documents().len(), 1);
+    assert!(app.run("file.open", json!({})).is_err());
+    assert_eq!(shown.requests().len(), 1);
+}
+
+#[test]
+fn save_as_goes_on_with_the_path_picked() {
+    let (mut app, shown, written) = app();
+    app.run("file.new", json!({"width": 100, "height": 80})).unwrap();
+    app.run("shape.rectangle", json!({"x": 10, "y": 10, "width": 30, "height": 20})).unwrap();
+    assert!(app.run("file.saveAs", json!({})).is_err());
+    assert!(matches!(shown.requests().as_slice(), [PickRequest::Save(_)]));
+    shown.answer(&["/art/poster.svg"]);
+    poll(&mut app);
+    // SVG Options asks next, and its OK writes the file there.
+    assert_eq!(app.ui.dialog.as_ref().map(|d| d.kind.as_str()), Some("svgOptions"));
+    crate::dialogs::confirm(&mut app).unwrap();
+    assert_eq!(*written.borrow(), ["/art/poster.svg"]);
+}
+
+#[test]
+fn a_dialogs_folder_button_fills_its_field_when_the_picker_answers() {
+    let (mut app, shown, _) = app();
+    let mut d = Dialog::new("exportForScreens", json!({"folder": ""}));
+    app.ui.dialog = Some(d.clone());
+    picks::folder_field(&mut app, &mut d, "folder");
+    assert_eq!(shown.requests(), [PickRequest::Folder]);
+    shown.answer(&["/out"]);
+    poll(&mut app);
+    assert_eq!(app.ui.dialog.as_ref().map(|d| d.str("folder")).as_deref(), Some("/out"));
+}

docs/mcp.md

@@ -2310,7 +2310,8 @@ tone (mono, or CMYK screens multiplied over each other), clipped to the art's ou
 
 Type can use the bundled fonts, fonts added to the session and the fonts installed on the system (none on the web):
 the system's and the user's font folders (Windows: `Fonts` and `%LOCALAPPDATA%\Microsoft\Windows\Fonts`, plus fonts
-registered outside them, such as fonts installed as shortcuts; macOS: `/System/Library/Fonts`, `/Library/Fonts`,
+registered outside them, such as fonts installed as shortcuts, and in the desktop app the fonts in DirectWrite's system
+font collection, such as those Adobe Fonts activates while Creative Cloud runs; macOS: `/System/Library/Fonts`, `/Library/Fonts`,
 `/Network/Library/Fonts`, `~/Library/Fonts` and downloaded system fonts; Linux and BSD: `/usr/share/fonts`,
 `/usr/local/share/fonts`, `~/.fonts` and the XDG data folders' `fonts`, `~/.local/share/fonts` among them, and in a
 Flatpak sandbox the host's fonts). The installed fonts are cataloged once per session (in the background when the app starts, else on the first lookup