merge: integrate round 11 (Shift/Ctrl on every select-mode click target, ranges on every multi-select surface, per-worktree build targets, SACD folder ticks) into pre-release

cc

.github/workflows/test-crates.yml

@@ -88,6 +88,7 @@ on:
       - "scripts/test-library-folders-qml.sh"
       - "scripts/test-array-model-qml.sh"
       - "scripts/test-keyed-model-qml.sh"
+      - "scripts/test-multi-select-qml.sh"
       - "scripts/test-wallpaper-field-qml.sh"
       - "scripts/test-card-menu-qml.sh"
       - "scripts/test-orbit-daemon.py"
@@ -120,6 +121,7 @@ on:
       - "scripts/test-library-folders-qml.sh"
       - "scripts/test-array-model-qml.sh"
       - "scripts/test-keyed-model-qml.sh"
+      - "scripts/test-multi-select-qml.sh"
       - "scripts/test-wallpaper-field-qml.sh"
       - "scripts/test-card-menu-qml.sh"
       - "scripts/test-orbit-daemon.py"

crates/qbz-qt/qml/cards/AlbumCard.qml

@@ -213,7 +213,10 @@ Rectangle {
     /// Park the select indicator bottom-right of the art instead of top-right.
     property bool selectMarkBottom: false
     property bool selected: false
-    signal selectToggled()
+    /// `modifiers` rides straight off the click: a grid host turns Shift into
+    /// a range (controls/SelectionModel.qml). Every select-mode target on the
+    /// card — artwork, title, artist line — emits it.
+    signal selectToggled(int modifiers)
 
     // Album blacklist ("Block this album") — LIVE since QbzBlacklist landed
     // (`blockAlbum(id, title, artist, coverUrl)`). Kept as a property, not
@@ -561,7 +564,7 @@ Rectangle {
                     }
                     // .slint:169 — in select mode the card click TOGGLES.
                     if (root.selectMode) {
-                        root.selectToggled()
+                        root.selectToggled(mouse.modifiers)
                         return
                     }
                     if (root.pulledDead)
@@ -993,7 +996,7 @@ Rectangle {
                             // .slint:465 — the title carries the SAME target
                             // as the artwork, select mode included.
                             if (root.selectMode) {
-                                root.selectToggled()
+                                root.selectToggled(mouse.modifiers)
                                 return
                             }
                             if (root.pulledDead)
@@ -1009,7 +1012,8 @@ Rectangle {
                     width: parent.width
                     height: 18
                     text: root.artist
-                    color: (root.artistId !== "" || root.hostArtistLink)
+                    color: !root.selectMode
+                        && (root.artistId !== "" || root.hostArtistLink)
                         && artistArea.containsMouse
                         ? theme.textPrimary : theme.textMuted
                     font.pixelSize: theme.fontLink - 1
@@ -1019,9 +1023,15 @@ Rectangle {
                         id: artistArea
                         anchors.fill: parent
                         hoverEnabled: true
-                        cursorShape: root.artistId !== "" || root.hostArtistLink
+                        cursorShape: root.selectMode || root.artistId !== "" || root.hostArtistLink
                             ? Qt.PointingHandCursor : Qt.ArrowCursor
-                        onClicked: {
+                        onClicked: function (mouse) {
+                            // In select mode the artist line is the card too:
+                            // opening the artist mid-selection would drop it.
+                            if (root.selectMode) {
+                                root.selectToggled(mouse.modifiers)
+                                return
+                            }
                             if (root.artistId !== "")
                                 QbzArtist.openArtist(root.artistId)
                             else if (root.hostArtistLink)

crates/qbz-qt/qml/controls/QbzCheckbox.qml

@@ -1,6 +1,11 @@
 // QbzCheckbox (primitives/QbzCheckbox.slint) — 18px square, r4, accent fill
-// with an accent-text check when on, muted border when off. Emits toggled();
-// like the Slint original it never self-flips (the owner of the state does).
+// with an accent-text check when on, muted border when off. Emits
+// toggled(modifiers); like the Slint original it never self-flips (the owner of
+// the state does).
+//
+// `modifiers` is the click's (or the key's), straight through: a multi-select
+// host turns Shift into a range (controls/SelectionModel.qml). Hosts that only
+// flip a flag keep a plain expression handler and never look at it.
 //
 // Used by Settings > Local Library (folder selection) and the Plex library
 // picker, i.e. every place the Slint uses its own QbzCheckbox.
@@ -15,7 +20,7 @@ Rectangle {
     id: root
 
     property bool checked: false
-    signal toggled()
+    signal toggled(int modifiers)
 
     QbzTheme { id: theme }
 
@@ -30,14 +35,14 @@ Rectangle {
     activeFocusOnTab: root.enabled
     Accessible.role: Accessible.CheckBox
     Accessible.checked: root.checked
-    Accessible.onToggleAction: if (root.enabled) root.toggled()
+    Accessible.onToggleAction: if (root.enabled) root.toggled(Qt.NoModifier)
 
     Keys.onPressed: function (event) {
         if (root.enabled && !event.isAutoRepeat
                 && (event.key === Qt.Key_Space
                     || event.key === Qt.Key_Return
                     || event.key === Qt.Key_Enter)) {
-            root.toggled()
+            root.toggled(event.modifiers)
             event.accepted = true
         }
     }
@@ -66,6 +71,6 @@ Rectangle {
         anchors.fill: parent
         cursorShape: Qt.PointingHandCursor
         onPressed: root.forceActiveFocus()
-        onClicked: root.toggled()
+        onClicked: function (mouse) { root.toggled(mouse.modifiers) }
     }
 }

crates/qbz-qt/qml/controls/SelectionModel.qml

@@ -40,6 +40,20 @@
 //
 // A NEW object is always returned: mutating a `var` map in place notifies
 // nothing, and every binding on it would go stale.
+//
+// ── EVERY CLICK TARGET MUST HAND ITS MODIFIERS OVER ───────────────────────
+// The rule only sees what the click target passes in. A select-mode surface
+// has more targets than its row body — the checkbox disc, the checkbox
+// controls, a whole album card, the name links drawn on a row — and each one
+// that called its host with no modifiers turned every Shift-click there into
+// a plain toggle. `scripts/qml-tests/tst_multi_select.qml` clicks all of them
+// through the real components.
+//
+// ── IDS COMPARE AS STRINGS ────────────────────────────────────────────────
+// `anchorId` is a string property, so a numeric id (an offline track id, a
+// settings folder id) was stored as "42" and then never found again among
+// rows carrying 42 — Shift silently degraded to a toggle. The selection map
+// keys are strings anyway, so comparing as strings is the same identity.
 
 import QtQuick
 
@@ -49,40 +63,94 @@ QtObject {
     /// The row a shift-range measures from. "" = no anchor yet. Hosts clear
     /// it when they leave select mode.
     property string anchorId: ""
+    /// The row field that identifies a row. Track and album rows use `id`;
+    /// the offline manager's rows carry `trackId`, the explorer facets `key`.
+    property string idKey: "id"
+
+    function _idOf(row) {
+        if (!row)
+            return ""
+        var value = row[root.idKey]
+        return value === undefined || value === null ? "" : String(value)
+    }
 
     function _indexOf(rows, id) {
+        var wanted = String(id)
         for (var i = 0; i < rows.length; i++)
-            if (rows[i] && rows[i].id === id)
+            if (root._idOf(rows[i]) === wanted)
                 return i
         return -1
     }
 
+    /// Adds every identified row between the anchor and `id` to `into`.
+    /// Rows without an id (group headers riding in the same list) are skipped.
+    function _fillRange(into, rows, anchorAt, here) {
+        var lo = Math.min(anchorAt, here)
+        var hi = Math.max(anchorAt, here)
+        for (var i = lo; i <= hi; i++) {
+            var rowId = root._idOf(rows[i])
+            if (rowId !== "")
+                into[rowId] = true
+        }
+        return into
+    }
+
     /// The selection map after clicking `id`, given the ordered `rows` the
     /// user is looking at and the `modifiers` off the mouse event.
     ///
     /// Pass the FILTERED rows when a view is filtered: a range over rows the
     /// user cannot see is not a range they asked for.
     function next(current, id, rows, modifiers) {
-        var shift = (modifiers & Qt.ShiftModifier) !== 0
+        var shift = ((modifiers || 0) & Qt.ShiftModifier) !== 0
         var anchorAt = root.anchorId !== "" ? root._indexOf(rows, root.anchorId) : -1
 
         if (shift && anchorAt >= 0) {
             var here = root._indexOf(rows, id)
-            if (here >= 0) {
-                var lo = Math.min(anchorAt, here)
-                var hi = Math.max(anchorAt, here)
-                var m = Object.assign({}, current)
-                for (var i = lo; i <= hi; i++)
-                    m[rows[i].id] = true
+            if (here >= 0)
                 // The anchor STAYS, so the same range can be re-dragged.
-                return m
-            }
+                return root._fillRange(Object.assign({}, current), rows, anchorAt, here)
         }
 
+        var key = String(id)
         var out = Object.assign({}, current)
-        if (out[id] === true) delete out[id]
-        else out[id] = true
-        root.anchorId = id
+        if (out[key] === true) delete out[key]
+        else out[key] = true
+        root.anchorId = key
+        return out
+    }
+
+    /// The spreadsheet / file-manager rule, for lists where a plain click
+    /// REPLACES the selection (the Library Explorer facets):
+    ///
+    ///   plain click    only this row; it becomes the anchor
+    ///   Ctrl / Cmd     toggle this row, keep the rest; it becomes the anchor
+    ///   Shift          only the range anchor..row; the anchor stays
+    ///   Ctrl+Shift     add the range anchor..row to the selection
+    ///
+    /// Without a visible anchor Shift behaves like the same click without it.
+    function nextExclusive(current, id, rows, modifiers) {
+        var mods = modifiers || 0
+        var shift = (mods & Qt.ShiftModifier) !== 0
+        var additive = (mods & (Qt.ControlModifier | Qt.MetaModifier)) !== 0
+        var key = String(id)
+        var anchorAt = root.anchorId !== "" ? root._indexOf(rows, root.anchorId) : -1
+
+        if (shift && anchorAt >= 0) {
+            var here = root._indexOf(rows, id)
+            if (here >= 0)
+                return root._fillRange(additive ? Object.assign({}, current) : {},
+                                       rows, anchorAt, here)
+        }
+
+        root.anchorId = key
+        if (!additive) {
+            var only = {}
+            only[key] = true
+            return only
+        }
+        var out = Object.assign({}, current)
+        if (out[key] === true) delete out[key]
+        else out[key] = true
         return out
     }
 }

crates/qbz-qt/qml/kiosk/KioskMyQBZDetailLite.qml

@@ -63,7 +63,7 @@ Rectangle {
         QbzMyQbz.kioskDetailArtwork(first, last, px)
     }
     function openRow(r) {
-        if (root.doc.selectMode) QbzMyQbz.detailToggleItemSelect(r.position)
+        if (root.doc.selectMode) QbzMyQbz.detailToggleItemSelect(r.position, false)
         else QbzMyQbz.openItem(r.source, r.itemType, r.sourceItemId)
     }
     function entry(label, action) { return {label: root.t(label), action: action} }

crates/qbz-qt/qml/rows/TrackRow.qml

@@ -749,7 +749,10 @@ Rectangle {
                     anchors.fill: parent
                     hoverEnabled: true
                     cursorShape: Qt.PointingHandCursor
-                    onClicked: root.toggleSelect(Qt.NoModifier)
+                    // The disc is where a select-mode click most often lands,
+                    // so it hands over the modifiers exactly like the body:
+                    // a plain `NoModifier` here made Shift-click a toggle.
+                    onClicked: function (mouse) { root.toggleSelect(mouse.modifiers) }
                 }
             }
             Text {
@@ -969,6 +972,9 @@ Rectangle {
                         MouseArea {
                             anchors.fill: parent
                             hoverEnabled: true
+                            // Hover only: a tooltip must not eat the click the
+                            // row body (play, or a select-mode toggle) owns.
+                            acceptedButtons: Qt.NoButton
                             ToolTip.visible: containsMouse
                             ToolTip.delay: 300
                             // NEW msgid — the one string this state needs and
@@ -1078,7 +1084,12 @@ Rectangle {
                 MouseArea {
                     id: artistLinkArea
                     anchors.fill: parent
-                    enabled: root.artistLink && (artistLine.linkMode || !!root.item.artistId)
+                    // In select mode the whole row is a selection target
+                    // (TrackRow.slint:174): the names stop being links so the
+                    // click — and its Shift / Ctrl — reaches the row body
+                    // instead of opening an artist page mid-selection.
+                    enabled: !root.selectMode
+                        && root.artistLink && (artistLine.linkMode || !!root.item.artistId)
                     hoverEnabled: true
                     cursorShape: (artistLine.linkMode
                                   ? (artistLine.hotSpan >= 0 && artistLine.spans[artistLine.hotSpan].href !== "")
@@ -1088,6 +1099,9 @@ Rectangle {
                             artistLine.hotSpan = artistLine.spanAt(mouse.x)
                     }
                     onExited: artistLine.hotSpan = -1
+                    // Entering select mode under the pointer disables the area
+                    // without an `exited`; the hot name must not stay lit.
+                    onEnabledChanged: if (!enabled) artistLine.hotSpan = -1
                     // Same routing as the menu's "Go to artist" — Slint drives
                     // both through one handler, so gating only the menu would
                     // leave the LINK navigating to the track's own artist.
@@ -1116,7 +1130,8 @@ Rectangle {
             MouseArea {
                 id: albumArea
                 anchors.fill: parent
-                enabled: !!root.item.albumId && !root.releaseGone
+                // Not a link in select mode, for the artist line's reason.
+                enabled: !root.selectMode && !!root.item.albumId && !root.releaseGone
                 hoverEnabled: true
                 cursorShape: Qt.PointingHandCursor
                 // The names ride along so a release the catalog lost can

crates/qbz-qt/qml/settings/LibraryFolderTable.qml

@@ -42,10 +42,23 @@ Column {
         })
     }
     function isSelected(id) { return selectedIds.indexOf(id) >= 0 }
-    function toggleSelected(id) {
-        const next = selectedIds.slice()
-        const at = next.indexOf(id)
-        if (at >= 0) next.splice(at, 1); else next.push(id)
+    /// A plain or Ctrl click toggles one folder; Shift adds the range from the
+    /// last plain click over the rows SHOWN (the filter is a view filter) —
+    /// the rule every multi-select list shares (controls/SelectionModel.qml).
+    SelectionModel { id: folderSel }
+    function toggleSelected(id, mods) {
+        const rows = root.shown()
+        const current = {}
+        for (let i = 0; i < selectedIds.length; i++)
+            current[String(selectedIds[i])] = true
+        const picked = folderSel.next(current, id, rows,
+                                      mods === undefined ? Qt.NoModifier : mods)
+        // Back to the ids themselves (the removal action takes them as
+        // numbers), keeping earlier picks the filter currently hides.
+        const next = selectedIds.filter(function (sid) { return picked[String(sid)] === true })
+        for (let j = 0; j < rows.length; j++)
+            if (picked[String(rows[j].id)] === true && next.indexOf(rows[j].id) < 0)
+                next.push(rows[j].id)
         selectedIds = next
     }
     function scanLabel(ts) {
@@ -118,6 +131,7 @@ Column {
                     QbzBridge.settingsString("library-remove-folders",
                         JSON.stringify(root.selectedIds))
                     root.selectedIds = []
+                    folderSel.anchorId = ""
                 }
             }
         }
@@ -279,7 +293,9 @@ Column {
                 anchors.fill: parent
                 hoverEnabled: true
                 cursorShape: Qt.PointingHandCursor
-                onClicked: root.toggleSelected(folderRow.modelData.id)
+                onClicked: function (mouse) {
+                    root.toggleSelected(folderRow.modelData.id, mouse.modifiers)
+                }
             }
 
             Row {
@@ -292,7 +308,9 @@ Column {
                     width: root.kioskHost ? 44 : 20
                     anchors.verticalCenter: parent.verticalCenter
                     checked: root.isSelected(folderRow.modelData.id)
-                    onToggled: root.toggleSelected(folderRow.modelData.id)
+                    onToggled: function (mods) {
+                        root.toggleSelected(folderRow.modelData.id, mods)
+                    }
                 }
                 // FOLDER: type glyph + name.
                 Row {

crates/qbz-qt/qml/shell/AppShell.qml

@@ -244,10 +244,11 @@ Rectangle {
     // in-view QML JS (library_bulk.rs:8: "select-all / clear never reach
     // Rust"), so the QbzShell signals route to the mounted view's
     // duck-typed interface: selectAll() / exitMultiSelectMode() /
-    // multiSelectOn. Implemented by LibraryView, LocalLibraryView and
-    // LocalAlbumView (MyQbzDetailView is EXIT-ONLY — its selection lives in
-    // Rust with no select-all arm); views without multi-select (Artist,
-    // Playlist, Mix, Label, Offline) match nothing — PARITY-DEBT (K4).
+    // multiSelectOn. Implemented by every view with a multi-select list:
+    // Library, Local Library, Local Album, Album, Artist, Playlist, Mix,
+    // Label and the Offline manager. MyQbzDetailView is EXIT-ONLY — its
+    // selection lives in Rust and its bar has no select-all arm (the Slint
+    // never had one there either).
     Connections {
         target: QbzShell
         function onSelectAllRequested() {

crates/qbz-qt/qml/views/AlbumListRow.qml

@@ -304,8 +304,11 @@ Rectangle {
                     id: artistArea
                     anchors.fill: parent
                     // Only a real artist id is clickable — otherwise the
-                    // pointer promises a page that cannot open.
-                    enabled: (root.item.artistId || "") !== ""
+                    // pointer promises a page that cannot open. In select
+                    // mode the whole row selects (Shift / Ctrl included), so
+                    // the name stops being a link and the click falls to the
+                    // row body underneath.
+                    enabled: !root.selectMode && (root.item.artistId || "") !== ""
                     hoverEnabled: true
                     cursorShape: Qt.PointingHandCursor
                     onClicked: QbzArtist.openArtist(root.item.artistId)
@@ -331,7 +334,8 @@ Rectangle {
                 MouseArea {
                     id: labelArea
                     anchors.fill: parent
-                    enabled: (root.item.labelId || "") !== ""
+                    // Not a link in select mode, for the artist name's reason.
+                    enabled: !root.selectMode && (root.item.labelId || "") !== ""
                     hoverEnabled: true
                     cursorShape: Qt.PointingHandCursor
                     onClicked: QbzHome.openLabel(root.item.labelId)

crates/qbz-qt/qml/views/ArtistView.qml

@@ -350,15 +350,18 @@ Rectangle {
     property string albumSelectKey: ""
     property var albumSelected: ({})
     readonly property int albumSelectedCount: Object.keys(root.albumSelected).length
-    function albumSelectToggle(id) {
-        var m = Object.assign({}, root.albumSelected)
-        if (m[id]) delete m[id]
-        else m[id] = true
-        root.albumSelected = m
+    /// The armed section's cards follow the same rule as every other
+    /// select-mode surface: Shift-click ranges over the section's cards in
+    /// their CURRENT sort order, Ctrl adds one (controls/SelectionModel.qml).
+    SelectionModel { id: albumSectionSel }
+    function albumSelectToggle(id, cards, mods) {
+        root.albumSelected = albumSectionSel.next(root.albumSelected, id, cards || [],
+                                                  mods === undefined ? Qt.NoModifier : mods)
     }
     function albumSelectClear() {
         root.albumSelectKey = ""
         root.albumSelected = ({})
+        albumSectionSel.anchorId = ""
     }
     function albumSectionLabel(key) {
         return root.albumSelectKey === key
@@ -393,6 +396,7 @@ Rectangle {
         } else if (action === "play-selected") {
             root.albumSelectKey = key
             root.albumSelected = ({})
+            albumSectionSel.anchorId = ""
         } else if (action === "cancel-selection") {
             root.albumSelectClear()
         }
@@ -2261,7 +2265,9 @@ Rectangle {
                     selectMode: root.albumSelectKey === (relSection.section.releaseType || "")
                     selected: root.albumSelected[modelData.id] === true
                     selectMarkBottom: true
-                    onSelectToggled: root.albumSelectToggle(modelData.id)
+                    onSelectToggled: function (mods) {
+                        root.albumSelectToggle(modelData.id, relSection.section.cards || [], mods)
+                    }
 
                     // ---- smooth append (owner, 2026-08-02) ---------------
                     // "que la aparicion de lo que se cargue, sea smooth" —
@@ -3273,7 +3279,9 @@ Rectangle {
                             selectMode: root.albumSelectKey === "library"
                             selected: root.albumSelected[modelData.id] === true
                             selectMarkBottom: true
-                            onSelectToggled: root.albumSelectToggle(modelData.id)
+                            onSelectToggled: function (mods) {
+                                root.albumSelectToggle(modelData.id, root.libAlbumsSorted, mods)
+                            }
                             albumId: modelData.id
                             title: modelData.title
                             artist: modelData.artist

crates/qbz-qt/qml/views/LocalLibraryView.qml

@@ -1187,23 +1187,42 @@ Rectangle {
         return sortRows(rows, genresSort)
     }
 
+    // The Explorer facets follow the spreadsheet rule — a plain click picks
+    // one value, Ctrl adds or removes one, Shift picks the run from the last
+    // click, Ctrl+Shift adds that run (SelectionModel.nextExclusive) — each
+    // column over its values AS LISTED (sorted, and filtered by its own
+    // search box). One anchor per column; a column whose values are rebuilt
+    // by a change upstream starts without one.
+    SelectionModel { id: genreFacetSel; idKey: "key" }
+    SelectionModel { id: yearFacetSel; idKey: "key" }
+    SelectionModel { id: artistFacetSel; idKey: "key" }
+    SelectionModel { id: albumFacetSel; idKey: "key" }
     function toggleGenre(key, modifiers) {
-        selectedGenres = nextFacetSelection(selectedGenres, key, modifiers)
+        selectedGenres = nextFacetSelection(genreFacetSel, selectedGenres, key, modifiers, genreNames)
         selectedGenreYears = ({})
         selectedGenreArtists = ({})
         selectedGenreAlbums = ({})
+        yearFacetSel.anchorId = ""
+        artistFacetSel.anchorId = ""
+        albumFacetSel.anchorId = ""
     }
     function toggleGenreYear(key, modifiers) {
-        selectedGenreYears = nextFacetSelection(selectedGenreYears, key, modifiers)
+        selectedGenreYears = nextFacetSelection(yearFacetSel, selectedGenreYears, key, modifiers,
+                                                genreYearOptions)
         selectedGenreArtists = ({})
         selectedGenreAlbums = ({})
+        artistFacetSel.anchorId = ""
+        albumFacetSel.anchorId = ""
     }
     function toggleGenreArtist(key, modifiers) {
-        selectedGenreArtists = nextFacetSelection(selectedGenreArtists, key, modifiers)
+        selectedGenreArtists = nextFacetSelection(artistFacetSel, selectedGenreArtists, key,
+                                                  modifiers, genreArtistOptions)
         selectedGenreAlbums = ({})
+        albumFacetSel.anchorId = ""
     }
     function toggleGenreAlbum(key, modifiers) {
-        selectedGenreAlbums = nextFacetSelection(selectedGenreAlbums, key, modifiers)
+        selectedGenreAlbums = nextFacetSelection(albumFacetSel, selectedGenreAlbums, key, modifiers,
+                                                 genreAlbumOptions)
     }
     function setExplorerColumns(mode) {
         if (["genre", "year", "both"].indexOf(mode) < 0 || mode === explorerColumns)
@@ -1219,17 +1238,14 @@ Rectangle {
     readonly property int explorerFacetCount: explorerColumns === "both" ? 4 : 3
     readonly property int explorerLeadingCount: explorerColumns === "year"
         ? genreYearOptions.length : genreNames.length
-    function nextFacetSelection(current, key, modifiers) {
-        if (key === "") return ({})
-        var additive = (modifiers & Qt.ControlModifier) !== 0
-            || (modifiers & Qt.MetaModifier) !== 0
-        if (!additive) {
-            var only = {}; only[key] = true; return only
+    /// `key` "" is the column's "All" row: it clears the column.
+    function nextFacetSelection(rule, current, key, modifiers, options) {
+        if (key === "") {
+            rule.anchorId = ""
+            return ({})
         }
-        var out = Object.assign({}, current)
-        if (out[key]) delete out[key]
-        else out[key] = true
-        return out
+        return rule.nextExclusive(current, key, options || [],
+                                  modifiers === undefined ? Qt.NoModifier : modifiers)
     }
 
     // The selected artist's albums.

crates/qbz-qt/qml/views/MixView.qml

@@ -124,7 +124,10 @@ Rectangle {
         if (action !== "add-to-playlist" && action !== "add-to-mixtape")
             root.selected = ({})
     }
-    // Ctrl+A / Escape hotkey seam (AppShell duck-types these).
+    // Ctrl+A / Escape hotkey seam (AppShell duck-types these). Without
+    // `multiSelectOn` the Escape stack never saw this view in select mode, so
+    // Escape did not leave it here while it did on every other track list.
+    readonly property bool multiSelectOn: root.multiSelect
     function selectAll() {
         if (!root.multiSelect) root.setMultiSelect(true)
         root.bulkAction("select-all")

crates/qbz-qt/qml/views/OfflineManagerView.qml

@@ -107,18 +107,34 @@ Rectangle {
         var p = root.livePatch[row.trackId]
         return (row.kind === "track" && p !== undefined) ? p.status : row.status
     }
-    function toggleSelect(trackId) {
-        var s = Object.assign({}, root.selected)
-        if (s[trackId] === true)
-            delete s[trackId]
-        else
-            s[trackId] = true
-        root.selected = s
+    /// The rule every multi-select list shares (controls/SelectionModel.qml):
+    /// a plain or Ctrl click toggles one track, Shift adds the range from the
+    /// last one — over the TRACK rows as drawn, never the album headers
+    /// between them. The Slint had this surface on its Shift-range table
+    /// (selection.rs SURFACE_OFFLINE); the port left it toggle-only.
+    SelectionModel { id: offlineSel; idKey: "trackId" }
+    function toggleSelect(trackId, mods) {
+        var tracks = root.rows.filter(function (row) { return row.kind === "track" })
+        root.selected = offlineSel.next(root.selected, trackId, tracks,
+                                        mods === undefined ? Qt.NoModifier : mods)
+    }
+
+    // Ctrl+A / Escape hotkey seam (AppShell duck-types these). The selection
+    // here is always on (no select mode), so Ctrl+A ticks every track — as
+    // the Slint's select_all_active_surface did for this view — and Escape
+    // drops a non-empty selection.
+    readonly property bool multiSelectOn: Object.keys(root.selected).length > 0
+    function selectAll() {
+        root.bulkAction("select-all")
+    }
+    function exitMultiSelectMode() {
+        root.bulkAction("clear")
     }
 
     function bulkAction(id) {
         if (id === "clear") {
             root.selected = ({})
+            offlineSel.anchorId = ""
             return
         }
         if (id === "select-all") {
@@ -507,8 +523,19 @@ Rectangle {
                                 hoverEnabled: true
                                 cursorShape: rowItem.isAlbum
                                     ? Qt.ArrowCursor : Qt.PointingHandCursor
-                                onClicked: if (!rowItem.isAlbum)
-                                    QbzOffline.playTrack(rowItem.modelData.trackId)
+                                // A plain click plays; a Shift or Ctrl click is
+                                // a selection gesture, as in any file list, so
+                                // it ticks (or ranges) instead of starting
+                                // playback.
+                                onClicked: function (mouse) {
+                                    if (rowItem.isAlbum)
+                                        return
+                                    if ((mouse.modifiers & (Qt.ShiftModifier | Qt.ControlModifier
+                                                            | Qt.MetaModifier)) !== 0)
+                                        root.toggleSelect(rowItem.modelData.trackId, mouse.modifiers)
+                                    else
+                                        QbzOffline.playTrack(rowItem.modelData.trackId)
+                                }
                             }
 
                             Row {
@@ -526,7 +553,9 @@ Rectangle {
                                         anchors.centerIn: parent
                                         visible: !rowItem.isAlbum
                                         checked: rowItem.checked
-                                        onToggled: root.toggleSelect(rowItem.modelData.trackId)
+                                        onToggled: function (mods) {
+                                            root.toggleSelect(rowItem.modelData.trackId, mods)
+                                        }
                                     }
                                 }
 

crates/qbz-qt/qml/views/local/LocalAlbumCollection.qml

@@ -593,11 +593,14 @@ Item {
                                 selected: root.nativeActive
                                     ? cardCell.slot.selected === true
                                     : root.selected[cardCell.slot.id] === true
-                                onSelectToggled: {
+                                // The card's modifiers, straight through: the
+                                // paged grid (299dcde5b) passed NoModifier here,
+                                // so a Shift-click on a card was a toggle.
+                                onSelectToggled: function (mods) {
                                     if (root.nativeActive)
-                                        root.nativeToggleSelect(cardCell.slot.nativeIndex, Qt.NoModifier)
+                                        root.nativeToggleSelect(cardCell.slot.nativeIndex, mods)
                                     else
-                                        root.toggleSelect(cardCell.slot.id, Qt.NoModifier)
+                                        root.toggleSelect(cardCell.slot.id, mods)
                                 }
                                 // Non-select mode only — the card routes a
                                 // select-mode click to `selectToggled` and never

crates/qbz-qt/qml/views/local/LocalTreeRail.qml

@@ -20,6 +20,52 @@ Item {
 
     QbzTheme { id: theme }
 
+    // ---- Shift / Ctrl on the rail's checkboxes ----
+    // The selection lives in RUST (QbzLocal.tree*Select owns the set of
+    // paths); what the rail holds is the one piece the rule needs on top of
+    // it, the ANCHOR: the path of the last plain or Ctrl click. A Shift-click
+    // looks it up among the rows drawn right now and SELECTS every row from
+    // there to the clicked one (QbzLocal.treeSelectRange — additive, like
+    // controls/SelectionModel.qml); an anchor that is not drawn any more
+    // (collapsed, filtered away) makes it a plain toggle again.
+    property string selectAnchor: ""
+    Connections {
+        target: root.view
+        function onTreeSelectModeChanged() {
+            if (!root.view.treeSelectMode)
+                root.selectAnchor = ""
+        }
+    }
+    /// The rows from `anchorPath` to `path`, inclusive, in rail order, as the
+    /// `{path, isFolder}` pairs treeSelectRange takes. [] when either is not
+    /// drawn.
+    function rangeNodes(rows, anchorPath, path) {
+        var from = -1
+        var to = -1
+        for (var i = 0; i < rows.length; i++) {
+            if (rows[i].path === anchorPath) from = i
+            if (rows[i].path === path) to = i
+        }
+        if (from < 0 || to < 0)
+            return []
+        var out = []
+        for (var j = Math.min(from, to); j <= Math.max(from, to); j++)
+            out.push({ "path": rows[j].path, "isFolder": rows[j].isFolder === true })
+        return out
+    }
+    function toggleNodeSelect(node, mods) {
+        if (((mods || 0) & Qt.ShiftModifier) !== 0 && root.selectAnchor !== "") {
+            var nodes = root.rangeNodes(root.view.tree || [], root.selectAnchor, node.path)
+            if (nodes.length > 0) {
+                QbzLocal.treeSelectRange(JSON.stringify(nodes))
+                return
+            }
+        }
+        if (node.isFolder) QbzLocal.treeToggleFolderSelect(node.path)
+        else QbzLocal.treeToggleTrackSelect(node.path)
+        root.selectAnchor = node.path
+    }
+
     Column {
         anchors.fill: parent
         anchors.leftMargin: 12
@@ -149,16 +195,9 @@ Item {
                     selectMode: root.view.treeSelectMode
                     onToggled: QbzLocal.treeToggle(modelData.path, !modelData.expanded)
                     onActivated: root.view.selectFolder(modelData.path)
-                    // NO Shift-range here, deliberately: this rail's selection
-                    // lives in RUST (QbzLocal.treeToggle*Select owns the set),
-                    // not in a QML map, so controls/SelectionModel.qml has
-                    // nothing to hold an anchor against. Giving the tree ranges
-                    // means teaching the Rust side about an anchor, which is a
-                    // change of its own and not part of this port.
-                    onToggleSelect: {
-                        if (modelData.isFolder) QbzLocal.treeToggleFolderSelect(modelData.path)
-                        else QbzLocal.treeToggleTrackSelect(modelData.path)
-                    }
+                    // Shift ranges from the rail's anchor (see
+                    // `toggleNodeSelect` at the top of this file).
+                    onToggleSelect: function (mods) { root.toggleNodeSelect(modelData, mods) }
                 }
             }
             QbzScrollBar {

crates/qbz-qt/qml/views/local/SelectCheck.qml

@@ -5,6 +5,10 @@
 // Slint declares this inline inside TreeRow; the Qt port also needs it on
 // the album cards and the track rows in multi-select, so it is its own file
 // (three call sites, one shape).
+//
+// `toggled` carries the click's modifiers: this disc IS a select-mode click
+// target, and one that dropped them turned every Shift-click on it into a
+// plain toggle (controls/SelectionModel.qml).
 
 import QtQuick
 import com.blitzfc.qbz
@@ -16,7 +20,7 @@ Rectangle {
     property bool on: false
     property bool partial: false
     property int diameter: 13
-    signal toggled()
+    signal toggled(int modifiers)
 
     QbzTheme { id: theme }
 
@@ -52,6 +56,6 @@ Rectangle {
         anchors.fill: parent
         hoverEnabled: true
         cursorShape: Qt.PointingHandCursor
-        onClicked: root.toggled()
+        onClicked: function (mouse) { root.toggled(mouse.modifiers) }
     }
 }

crates/qbz-qt/qml/views/local/TreeRow.qml

@@ -50,6 +50,15 @@ Rectangle {
                 if (root.node.isFolder) folderMenu.openAtCursor(rowArea, mouse.x, mouse.y)
                 return
             }
+            // In select mode a Shift or Ctrl click on the body is a selection
+            // gesture, as in any file list: it ticks (or ranges) the row
+            // instead of opening the folder. A plain click still opens it.
+            if (root.selectMode
+                    && (mouse.modifiers & (Qt.ShiftModifier | Qt.ControlModifier
+                                           | Qt.MetaModifier)) !== 0) {
+                root.toggleSelect(mouse.modifiers)
+                return
+            }
             if (root.node.isFolder) root.activated()
         }
     }

crates/qbz-qt/qml/views/myqbz/MyQbzDetailRow.qml

@@ -171,7 +171,9 @@ Rectangle {
         }
         onClicked: function (mouse) {
             if (mouse.button !== Qt.LeftButton) return
-            if (root.selectMode) QbzMyQbz.detailToggleItemSelect(root.itemPosition)
+            if (root.selectMode)
+                QbzMyQbz.detailToggleItemSelect(root.itemPosition,
+                                                (mouse.modifiers & Qt.ShiftModifier) !== 0)
             else root.openThis()
         }
     }
@@ -247,7 +249,10 @@ Rectangle {
                 visible: root.selectMode
                 anchors.centerIn: parent
                 on: root.selected
-                onToggled: QbzMyQbz.detailToggleItemSelect(root.itemPosition)
+                onToggled: function (mods) {
+                    QbzMyQbz.detailToggleItemSelect(root.itemPosition,
+                                                    (mods & Qt.ShiftModifier) !== 0)
+                }
             }
         }
 
@@ -295,6 +300,10 @@ Rectangle {
                 MouseArea {
                     id: artArea
                     anchors.fill: parent
+                    // In select mode the whole row selects (Shift / Ctrl
+                    // included): the artwork, title and artist stop playing
+                    // or navigating so the click reaches the row body.
+                    enabled: !root.selectMode
                     hoverEnabled: true
                     cursorShape: Qt.PointingHandCursor
                     onClicked: QbzMyQbz.playItem(root.sourceItemId)
@@ -321,6 +330,7 @@ Rectangle {
                     MouseArea {
                         id: titleArea
                         anchors.fill: parent
+                        enabled: !root.selectMode
                         hoverEnabled: true
                         cursorShape: Qt.PointingHandCursor
                         onClicked: root.openThis()
@@ -343,6 +353,7 @@ Rectangle {
                     MouseArea {
                         id: subArea
                         anchors.fill: parent
+                        enabled: !root.selectMode
                         hoverEnabled: true
                         cursorShape: root.subtitleIsLink ? Qt.PointingHandCursor : Qt.ArrowCursor
                         onClicked: {

crates/qbz-qt/qml/views/myqbz/MyQbzDetailView.qml

@@ -1193,7 +1193,10 @@ Rectangle {
                             // selection checkbox rather than bolt one on.
                             selectMode: root.selectMode
                             selected: gcell.cSelected
-                            onSelectToggled: QbzMyQbz.detailToggleItemSelect(gcell.cPosition)
+                            onSelectToggled: function (mods) {
+                                QbzMyQbz.detailToggleItemSelect(gcell.cPosition,
+                                    (mods & Qt.ShiftModifier) !== 0)
+                            }
                             // Card body click, non-select mode only (the card
                             // routes a select-mode click to `selectToggled`).
                             onOpenRequested: QbzMyQbz.openItem(gcell.cSource,

crates/qbz-qt/src/local_bridge.rs

@@ -365,6 +365,11 @@ pub mod qbz_local {
         /// Track checkbox: toggle one row by file path.
         #[qinvokable]
         fn tree_toggle_track_select(self: Pin<&mut QbzLocal>, path: QString);
+        /// Shift-click on a rail checkbox: SELECT every visible row from the
+        /// anchor to the clicked one. `nodes_json` =
+        /// `[{"path": …, "isFolder": …}]` in rail order.
+        #[qinvokable]
+        fn tree_select_range(self: Pin<&mut QbzLocal>, nodes_json: QString);
         /// Tree-rail bulk bar.
         #[qinvokable]
         fn folders_bulk_action(self: Pin<&mut QbzLocal>, action: QString);
@@ -1757,6 +1762,10 @@ impl qbz_local::QbzLocal {
         crate::local_bulk::toggle_track_select(path.to_string());
     }
 
+    pub fn tree_select_range(self: Pin<&mut Self>, nodes_json: QString) {
+        crate::local_bulk::select_tree_range(nodes_json.to_string());
+    }
+
     pub fn folders_bulk_action(self: Pin<&mut Self>, action: QString) {
         crate::local_bulk::folders_bulk_action(action.to_string());
     }

crates/qbz-qt/src/local_bulk.rs

@@ -24,7 +24,9 @@
 //! This file is the Qt-facing half of the tree selection; the state and the
 //! blocking mutators live in `local_tree.rs`, next to the tree they annotate.
 
-use std::collections::HashMap;
+use std::collections::{HashMap, VecDeque};
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::sync::Mutex;
 
 use cxx_qt_lib::QString;
 use qbz_library::LocalTrack;
@@ -61,29 +63,124 @@ fn publish_selection() {
 // ---------------------------------------------------------------------------
 
 /// Rail header toggle. Leaving select mode drops the selection, so the
-/// republish is what hollows every checkbox again.
+/// republish is what hollows every checkbox again. The drop waits behind any
+/// checkbox click still queued, or that click would tick a row again after it.
 pub fn set_select_mode(on: bool) {
-    tree::set_tree_select_mode(on);
-    publish_selection();
+    if on {
+        publish_selection();
+    } else {
+        run_tree_select(TreeSelectOp::LeaveSelectMode);
+    }
+}
+
+/// One tree-selection mutation, as the user issued it.
+enum TreeSelectOp {
+    Folder(String),
+    Track(String),
+    Range(Vec<(String, bool)>),
+    SelectAll,
+    Clear,
+    LeaveSelectMode,
+}
+
+/// The rail's selection mutations run ONE AT A TIME, in the order they were
+/// clicked. Each is a blocking DB read, and they used to be spawned side by
+/// side: harmless while every click was a toggle of its own row, but a
+/// Shift-range that finished before the plain click that set its anchor would
+/// see that folder already selected by the range — and the late toggle would
+/// then UNselect it. Clicks push here on the Qt thread, so the queue order is
+/// the click order; a single drainer works through it.
+static TREE_SELECT_OPS: Mutex<VecDeque<TreeSelectOp>> = Mutex::new(VecDeque::new());
+static TREE_SELECT_DRAINING: AtomicBool = AtomicBool::new(false);
+
+fn run_tree_select(op: TreeSelectOp) {
+    TREE_SELECT_OPS
+        .lock()
+        .unwrap_or_else(|e| e.into_inner())
+        .push_back(op);
+    if TREE_SELECT_DRAINING.swap(true, Ordering::SeqCst) {
+        return;
+    }
+    crate::spawn(async move {
+        // A drainer that dies mid-queue must not leave the flag up, or no
+        // later click would ever be applied.
+        struct Unwedge;
+        impl Drop for Unwedge {
+            fn drop(&mut self) {
+                if std::thread::panicking() {
+                    TREE_SELECT_DRAINING.store(false, Ordering::SeqCst);
+                }
+            }
+        }
+        let _unwedge = Unwedge;
+        loop {
+            let next = TREE_SELECT_OPS
+                .lock()
+                .unwrap_or_else(|e| e.into_inner())
+                .pop_front();
+            let Some(op) = next else {
+                TREE_SELECT_DRAINING.store(false, Ordering::SeqCst);
+                // A click that queued between the empty pop and the store saw
+                // a drainer still running and spawned none: take it over.
+                let pending = !TREE_SELECT_OPS
+                    .lock()
+                    .unwrap_or_else(|e| e.into_inner())
+                    .is_empty();
+                if pending && !TREE_SELECT_DRAINING.swap(true, Ordering::SeqCst) {
+                    continue;
+                }
+                break;
+            };
+            let _ = tokio::task::spawn_blocking(move || match op {
+                TreeSelectOp::Folder(path) => tree::toggle_folder_select_blocking(&path),
+                TreeSelectOp::Track(path) => tree::toggle_track_select_blocking(&path),
+                TreeSelectOp::Range(nodes) => tree::select_nodes_blocking(&nodes),
+                TreeSelectOp::SelectAll => tree::tree_select_all_blocking(),
+                TreeSelectOp::Clear => tree::tree_clear_selection(),
+                TreeSelectOp::LeaveSelectMode => tree::set_tree_select_mode(false),
+            })
+            .await;
+            publish_selection();
+        }
+    });
 }
 
 /// Folder checkbox: recursive, so it is a DB read on a blocking thread.
 pub fn toggle_folder_select(path: String) {
-    crate::spawn(async move {
-        let _ =
-            tokio::task::spawn_blocking(move || tree::toggle_folder_select_blocking(&path)).await;
-        publish_selection();
-    });
+    run_tree_select(TreeSelectOp::Folder(path));
 }
 
 /// Track checkbox: a deselect is pure state, a select resolves the record
 /// from the parent folder listing — blocking either way.
 pub fn toggle_track_select(path: String) {
-    crate::spawn(async move {
-        let _ =
-            tokio::task::spawn_blocking(move || tree::toggle_track_select_blocking(&path)).await;
-        publish_selection();
-    });
+    run_tree_select(TreeSelectOp::Track(path));
+}
+
+/// Shift-click on a rail checkbox: `nodes_json` is the visible rows from the
+/// anchor to the clicked one, `[{"path": …, "isFolder": …}]`, all SELECTED
+/// (`local_tree::select_nodes_blocking`).
+pub fn select_tree_range(nodes_json: String) {
+    let nodes = parse_tree_range(&nodes_json);
+    if nodes.is_empty() {
+        return;
+    }
+    run_tree_select(TreeSelectOp::Range(nodes));
+}
+
+fn parse_tree_range(json: &str) -> Vec<(String, bool)> {
+    #[derive(serde::Deserialize)]
+    struct Node {
+        #[serde(default)]
+        path: String,
+        #[serde(rename = "isFolder", default)]
+        is_folder: bool,
+    }
+    serde_json::from_str::<Vec<Node>>(json)
+        .unwrap_or_default()
+        .into_iter()
+        .filter(|node| !node.path.is_empty())
+        .map(|node| (node.path, node.is_folder))
+        .collect()
 }
 
 // ---------------------------------------------------------------------------
@@ -99,16 +196,11 @@ pub fn toggle_track_select(path: String) {
 pub fn folders_bulk_action(action: String) {
     match action.as_str() {
         "select-all" => {
-            // Two-way: "check all" un-checks when everything already is.
-            crate::spawn(async move {
-                let _ = tokio::task::spawn_blocking(tree::tree_select_all_blocking).await;
-                publish_selection();
-            });
-        }
-        "clear" => {
-            tree::tree_clear_selection();
-            publish_selection();
+            // Two-way: "check all" un-checks when everything already is. In
+            // the same queue as the checkboxes, so it sees them all applied.
+            run_tree_select(TreeSelectOp::SelectAll);
         }
+        "clear" => run_tree_select(TreeSelectOp::Clear),
         _ => {
             let rows = tree::tree_selected_snapshot();
             crate::spawn(async move {
@@ -336,3 +428,30 @@ async fn enqueue_rows(rows: Vec<LocalTrack>, mode: &str) {
     }
     crate::playback_qt::publish_queue(&runtime).await;
 }
+
+#[cfg(test)]
+mod tree_range_tests {
+    use super::parse_tree_range;
+
+    #[test]
+    fn range_nodes_keep_their_order_and_kind() {
+        let nodes = parse_tree_range(
+            r#"[{"path":"/m/a","isFolder":true},{"path":"/m/a/1.flac","isFolder":false},{"path":"/m/b","isFolder":true}]"#,
+        );
+        assert_eq!(
+            nodes,
+            vec![
+                ("/m/a".to_string(), true),
+                ("/m/a/1.flac".to_string(), false),
+                ("/m/b".to_string(), true),
+            ]
+        );
+    }
+
+    #[test]
+    fn range_nodes_without_a_path_or_bad_json_are_dropped() {
+        assert!(parse_tree_range("not json").is_empty());
+        let nodes = parse_tree_range(r#"[{"isFolder":true},{"path":"/m/c"}]"#);
+        assert_eq!(nodes, vec![("/m/c".to_string(), false)]);
+    }
+}

crates/qbz-qt/src/local_tree.rs

@@ -260,6 +260,33 @@ fn sel<R>(f: impl FnOnce(&mut HashMap<String, LocalTrack>) -> R) -> R {
     f(guard.get_or_insert_with(HashMap::new))
 }
 
+/// How many selected keys lie under the folder node `folder`. `paths` is the
+/// SORTED selection.
+///
+/// Ordinary tracks are keyed by their file path, `<folder>/…`. SACD tracks are
+/// keyed by their virtual path `sacd:<image>#N`: under an ancestor folder that
+/// reads `sacd:<folder>/…`, and under the image's own synthetic folder node
+/// (whose path IS the image) `sacd:<image>#…`. Counting only `<folder>/…` left
+/// every folder holding ISOs hollow or partial while its tracks were selected.
+///
+/// Each form is a byte-order range: every key starting with a prefix sorts
+/// between the prefix and the prefix with its last byte bumped by one ('/'
+/// 0x2F -> '0', '#' 0x23 -> '$'); the three ranges are disjoint.
+fn selected_under(paths: &[String], folder: &str) -> u32 {
+    let range = |prefix: String| {
+        let mut upper = prefix.clone().into_bytes();
+        if let Some(last) = upper.last_mut() {
+            *last += 1;
+        }
+        let upper = String::from_utf8(upper).unwrap_or_default();
+        let start = paths.partition_point(|p| p.as_str() < prefix.as_str());
+        let end = paths.partition_point(|p| p.as_str() < upper.as_str());
+        end.saturating_sub(start)
+    };
+    (range(format!("{folder}/")) + range(format!("sacd:{folder}/")) + range(format!("sacd:{folder}#")))
+        as u32
+}
+
 /// Annotate the visible rows. ONE sorted view of the selected paths is built
 /// per publish; each folder's "how many of my tracks are selected" is then a
 /// binary-searched range and each track row a binary search — instead of the
@@ -282,14 +309,7 @@ fn annotate(nodes: Vec<TreeNode>) -> Vec<TreeNodeOut> {
         .into_iter()
         .map(|node| {
             let (selected, select_state) = if node.is_folder {
-                // Byte-order range over "<path>/…": the upper bound is the
-                // same prefix with its trailing '/' (0x2F) bumped to '0'
-                // (0x30), which is the next byte value.
-                let lo = format!("{}/", node.path);
-                let hi = format!("{}0", node.path);
-                let start = paths.partition_point(|p| p.as_str() < lo.as_str());
-                let end = paths.partition_point(|p| p.as_str() < hi.as_str());
-                let under = (end - start) as u32;
+                let under = selected_under(&paths, &node.path);
                 let st = if under == 0 {
                     0
                 } else if node.track_count > 0 && under >= node.track_count {
@@ -364,25 +384,54 @@ pub fn toggle_track_select_blocking(path: &str) {
     if sel(|s| s.remove(path)).is_some() {
         return;
     }
-    // SACD leaves deliberately carry their authoritative virtual
-    // `sacd:<image>#N` path, whose filesystem parent is not the synthetic ISO
-    // folder shown in the tree. Resolve the exact key first; ordinary files
-    // take this same cheap indexed path and no longer need a parent listing.
-    if let Some(track) = with_db(|db| db.get_track_by_path(path)).flatten() {
+    if let Some(track) = resolve_track_record(path) {
         sel(|s| {
             s.insert(path.to_string(), track);
         });
-        return;
+    }
+}
+
+/// The library record behind a track leaf's path.
+///
+/// SACD leaves deliberately carry their authoritative virtual
+/// `sacd:<image>#N` path, whose filesystem parent is not the synthetic ISO
+/// folder shown in the tree. Resolve the exact key first; ordinary files take
+/// this same cheap indexed path and no longer need a parent listing.
+fn resolve_track_record(path: &str) -> Option<LocalTrack> {
+    if let Some(track) = with_db(|db| db.get_track_by_path(path)).flatten() {
+        return Some(track);
     }
     let parent = std::path::Path::new(path)
         .parent()
         .map(|p| p.to_string_lossy().into_owned())
         .unwrap_or_default();
     let tracks = with_db(|db| db.list_folder_tracks(&parent, false)).unwrap_or_default();
-    if let Some(t) = tracks.into_iter().find(|t| t.file_path == path) {
-        sel(|s| {
-            s.insert(path.to_string(), t);
-        });
+    tracks.into_iter().find(|t| t.file_path == path)
+}
+
+/// Shift-click in the rail: SELECT — never toggle — every node the range
+/// covers (`nodes` = `(path, is_folder)` of the visible rows from the anchor
+/// to the clicked row). A folder brings its whole subtree and a track its own
+/// record. Inserting is idempotent, so a folder and its expanded children
+/// sharing the range, or rows that were already ticked, simply stay ticked:
+/// a range only ever adds, like every other select-mode surface.
+pub fn select_nodes_blocking(nodes: &[(String, bool)]) {
+    for (path, is_folder) in nodes {
+        if *is_folder {
+            let tracks =
+                with_db(|db| db.list_folder_tracks_recursive(path, false)).unwrap_or_default();
+            sel(|s| {
+                for t in tracks {
+                    s.insert(t.file_path.clone(), t);
+                }
+            });
+        } else if !sel(|s| s.contains_key(path.as_str())) {
+            if let Some(track) = resolve_track_record(path) {
+                sel(|s| {
+                    s.insert(path.clone(), track);
+                });
+            }
+        }
     }
 }
 
@@ -460,3 +509,43 @@ pub fn load_folder_detail_blocking(path: &str) -> FolderDetail {
         tracks: rows,
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::selected_under;
+
+    fn sorted(keys: &[&str]) -> Vec<String> {
+        let mut out: Vec<String> = keys.iter().map(|k| k.to_string()).collect();
+        out.sort_unstable();
+        out
+    }
+
+    #[test]
+    fn sacd_tracks_count_under_their_folders_and_their_image() {
+        let paths = sorted(&[
+            "/m/DSD/A/a-ha/01.dsf",
+            "sacd:/m/DSD/A/a-ha/Hunting.iso#1",
+            "sacd:/m/DSD/A/a-ha/Hunting.iso#2",
+            "sacd:/m/DSD/B/Bowie.iso#1",
+        ]);
+        assert_eq!(selected_under(&paths, "/m/DSD/A"), 3);
+        assert_eq!(selected_under(&paths, "/m/DSD/A/a-ha"), 3);
+        assert_eq!(selected_under(&paths, "/m/DSD/A/a-ha/Hunting.iso"), 2);
+        assert_eq!(selected_under(&paths, "/m/DSD"), 4);
+        assert_eq!(selected_under(&paths, "/m/DSD/B"), 1);
+    }
+
+    #[test]
+    fn sibling_prefixes_and_other_images_are_not_counted() {
+        let paths = sorted(&[
+            "/m/ab/01.flac",
+            "sacd:/m/ab/x.iso#1",
+            "sacd:/m/a.iso2#1",
+            "sacd:/m/a.iso#3",
+        ]);
+        assert_eq!(selected_under(&paths, "/m/a"), 0);
+        assert_eq!(selected_under(&paths, "/m/a.iso"), 1);
+        assert_eq!(selected_under(&paths, "/m/ab"), 2);
+        assert_eq!(selected_under(&[], "/m"), 0);
+    }
+}

crates/qbz-qt/src/myqbz_bridge.rs

@@ -162,9 +162,11 @@ pub mod qbz_myqbz_bridge {
         /// Leaving select mode clears the selection.
         #[qinvokable]
         fn detail_toggle_select_mode(self: Pin<&mut QbzMyQbz>);
-        /// `position` is the 0-based persisted position (the stable key).
+        /// `position` is the 0-based persisted position (the stable key);
+        /// `shift` = the click held Shift, i.e. add the range from the last
+        /// plain click (myqbz_detail_qt::toggle_item_select).
         #[qinvokable]
-        fn detail_toggle_item_select(self: Pin<&mut QbzMyQbz>, position: i32);
+        fn detail_toggle_item_select(self: Pin<&mut QbzMyQbz>, position: i32, shift: bool);
         /// Resets type/source/sort; the search text is left INTACT
         /// (myqbz_detail.rs:540-541).
         #[qinvokable]
@@ -472,8 +474,8 @@ impl qbz_myqbz_bridge::QbzMyQbz {
         crate::myqbz_detail_qt::toggle_select_mode();
     }
 
-    pub fn detail_toggle_item_select(self: Pin<&mut Self>, position: i32) {
-        crate::myqbz_detail_qt::toggle_item_select(position);
+    pub fn detail_toggle_item_select(self: Pin<&mut Self>, position: i32, shift: bool) {
+        crate::myqbz_detail_qt::toggle_item_select(position, shift);
     }
 
     pub fn detail_reset_filters(self: Pin<&mut Self>) {

crates/qbz-qt/src/myqbz_detail_qt.rs

@@ -463,6 +463,43 @@ static RESOLVE_CACHE: LazyLock<Mutex<HashMap<String, ResolvedItem>>> =
 /// the bulk actions in agreement with what the user sees (spec 02 §12 #13).
 static SELECTED: LazyLock<Mutex<HashSet<i32>>> = LazyLock::new(|| Mutex::new(HashSet::new()));
 
+/// The POSITION a Shift-click ranges from (the last plain or Ctrl click).
+/// Dropped wherever `SELECTED` is cleared, so a range never measures from a
+/// row of a previous derive. Lock order: DOC, then SELECTED, then this.
+static SELECT_ANCHOR: Mutex<Option<i32>> = Mutex::new(None);
+
+fn clear_select_anchor() {
+    *SELECT_ANCHOR.lock().unwrap() = None;
+}
+
+/// One select-mode click over the rows as DRAWN (`order` = the rendered
+/// positions, top to bottom). The rule every select-mode surface shares
+/// (qml/controls/SelectionModel.qml): a plain or Ctrl click toggles `position`
+/// and becomes the anchor; Shift ADDS every row from the anchor to `position`
+/// and leaves the anchor where it is, so the range can be adjusted. Without a
+/// drawn anchor a Shift-click is a plain toggle.
+fn apply_item_click(
+    order: &[i32],
+    selected: &mut HashSet<i32>,
+    anchor: &mut Option<i32>,
+    position: i32,
+    shift: bool,
+) {
+    if shift {
+        let from = anchor.and_then(|a| order.iter().position(|p| *p == a));
+        let to = order.iter().position(|p| *p == position);
+        if let (Some(from), Some(to)) = (from, to) {
+            let (lo, hi) = if from <= to { (from, to) } else { (to, from) };
+            selected.extend(order[lo..=hi].iter().copied());
+            return;
+        }
+    }
+    if !selected.remove(&position) {
+        selected.insert(position);
+    }
+    *anchor = Some(position);
+}
+
 /// Fingerprint of the last derive's filter/sort/search inputs — what decides
 /// whether a rebuild is a RE-DERIVE (clears the selection) or a row patch.
 static LAST_FILTER_KEY: Mutex<Option<String>> = Mutex::new(None);
@@ -1080,6 +1117,7 @@ fn rebuild(d: &mut DetailDoc) {
         // reference, the COUNT below is recomputed from the same set, so the
         // bulk bar can never claim a selection the rows do not show.
         SELECTED.lock().unwrap().clear();
+        clear_select_anchor();
     }
 
     let view = filtered_sorted(d);
@@ -1431,6 +1469,7 @@ fn reset() {
     // `apply` seeds this one back from it.
     OPEN_ROWS.lock().unwrap().clear();
     SELECTED.lock().unwrap().clear();
+    clear_select_anchor();
     *LAST_FILTER_KEY.lock().unwrap() = None;
     // Close the persist gate until `apply` restores this collection's prefs.
     PREFS_HYDRATED.store(false, Ordering::SeqCst);
@@ -2158,6 +2197,7 @@ pub(crate) fn toggle_select_mode() {
         let on = !d.select_mode;
         if !on {
             SELECTED.lock().unwrap().clear();
+            clear_select_anchor();
             for row in d.items.iter_mut() {
                 row.selected = false;
             }
@@ -2169,24 +2209,19 @@ pub(crate) fn toggle_select_mode() {
     publish(&doc);
 }
 
-/// Toggle one row's selection by its stable POSITION, then recount. A row patch
-/// — never a re-derive.
-pub(crate) fn toggle_item_select(position: i32) {
+/// One select-mode click on a row, by its stable POSITION: a toggle, or with
+/// `shift` the range from the anchor (`apply_item_click`). Then every drawn
+/// row's tick and the count follow the set. A row patch — never a re-derive.
+pub(crate) fn toggle_item_select(position: i32, shift: bool) {
     let doc = with_doc(|d| {
-        let now_selected = {
-            let mut set = SELECTED.lock().unwrap();
-            if set.contains(&position) {
-                set.remove(&position);
-                false
-            } else {
-                set.insert(position);
-                true
-            }
-        };
-        if let Some(row) = d.items.iter_mut().find(|r| r.position == position) {
-            row.selected = now_selected;
+        let order: Vec<i32> = d.items.iter().map(|r| r.position).collect();
+        let mut set = SELECTED.lock().unwrap();
+        let mut anchor = SELECT_ANCHOR.lock().unwrap();
+        apply_item_click(&order, &mut set, &mut anchor, position, shift);
+        for row in d.items.iter_mut() {
+            row.selected = set.contains(&row.position);
         }
-        d.selected_count = SELECTED.lock().unwrap().len() as i32;
+        d.selected_count = set.len() as i32;
         d.clone()
     });
     publish(&doc);
@@ -2197,6 +2232,7 @@ pub(crate) fn toggle_item_select(position: i32) {
 pub(crate) fn clear_selection() {
     let doc = with_doc(|d| {
         SELECTED.lock().unwrap().clear();
+        clear_select_anchor();
         for row in d.items.iter_mut() {
             row.selected = false;
         }
@@ -2374,6 +2410,7 @@ pub(crate) fn teardown() {
     RESOLVE_CACHE.lock().unwrap().clear();
     OPEN_ROWS.lock().unwrap().clear();
     SELECTED.lock().unwrap().clear();
+    clear_select_anchor();
     *LAST_FILTER_KEY.lock().unwrap() = None;
     PREFS_HYDRATED.store(false, Ordering::SeqCst);
     let doc = with_doc(|d| {
@@ -2495,6 +2532,45 @@ pub(crate) fn bulk_action(id: String) {
 mod tests {
     use super::*;
 
+    fn picked(set: &HashSet<i32>) -> Vec<i32> {
+        let mut out: Vec<i32> = set.iter().copied().collect();
+        out.sort_unstable();
+        out
+    }
+
+    #[test]
+    fn select_click_ranges_over_the_drawn_order() {
+        // Rows drawn in a sorted order that is NOT the position order.
+        let order = [4, 0, 7, 2, 9, 5];
+        let mut set = HashSet::new();
+        let mut anchor = None;
+        apply_item_click(&order, &mut set, &mut anchor, 0, false);
+        assert_eq!(anchor, Some(0));
+        apply_item_click(&order, &mut set, &mut anchor, 9, true);
+        // 0, 7, 2, 9 are the drawn rows between them; 4 and 5 are outside.
+        assert_eq!(picked(&set), vec![0, 2, 7, 9]);
+        assert_eq!(anchor, Some(0), "a Shift-click keeps the anchor");
+        // Re-dragging the range upward only ever adds.
+        apply_item_click(&order, &mut set, &mut anchor, 4, true);
+        assert_eq!(picked(&set), vec![0, 2, 4, 7, 9]);
+    }
+
+    #[test]
+    fn select_click_toggles_and_moves_the_anchor() {
+        let order = [1, 2, 3, 4];
+        let mut set = HashSet::new();
+        let mut anchor = None;
+        apply_item_click(&order, &mut set, &mut anchor, 3, false);
+        apply_item_click(&order, &mut set, &mut anchor, 3, false);
+        assert!(set.is_empty(), "a second plain click unticks the row");
+        assert_eq!(anchor, Some(3));
+        // Shift without a drawn anchor is a plain toggle that anchors there.
+        let mut gone = Some(42);
+        apply_item_click(&order, &mut set, &mut gone, 2, true);
+        assert_eq!(picked(&set), vec![2]);
+        assert_eq!(gone, Some(2));
+    }
+
     fn item(
         position: i32,
         title: &str,

scripts/build-aarch64-linux.sh

@@ -89,8 +89,11 @@ case "$arch" in
     else jobs="$(nproc)"; fi
     say "RAM ${mem_mb} MB -> CARGO_BUILD_JOBS=${jobs}"
     # No RUSTFLAGS, no mold, stable: same cache rule as qt-run.sh.
+    # The target qt-cargo.py builds in (scripts/qt-target.py), resolved once.
+    CARGO_TARGET_DIR="$(python3 scripts/qt-target.py resolve)"
+    export CARGO_TARGET_DIR
     CARGO_BUILD_JOBS="$jobs" CARGO_INCREMENTAL=0 python3 scripts/qt-cargo.py build --release --manifest-path crates/Cargo.toml -p qbz-qt
-    install -Dm755 "crates/target/release/qbz" "$OUT"
+    install -Dm755 "$CARGO_TARGET_DIR/release/qbz" "$OUT"
     ;;
   x86_64 | amd64)
     die "CROSS mode is not supported for the Qt binary (see the header: cxx-qt \

scripts/build-aarch64-qbzd.sh

@@ -48,8 +48,12 @@ case "$arch" in
     else
       echo "[qbzd-aarch64] non-apt distro: install the equivalents of: ${DEPS[*]}" >&2
     fi
+    # This worktree's own target (scripts/qt-target.py): Cargo's default in a
+    # plain checkout, a per-worktree sibling when the host shares one target.
+    CARGO_TARGET_DIR="$(python3 scripts/qt-target.py resolve)"
+    export CARGO_TARGET_DIR
     ( cd crates && cargo build --release -p qbzd )
-    install -Dm755 "crates/target/release/qbzd" "$OUT"
+    install -Dm755 "$CARGO_TARGET_DIR/release/qbzd" "$OUT"
     ;;
   x86_64 | amd64)
     echo "[qbzd-aarch64] CROSS-compile from $arch via cross (Docker)"
@@ -65,8 +69,12 @@ case "$arch" in
     export CROSS_CONTAINER_OPTS="${CROSS_CONTAINER_OPTS:---memory=8g --memory-swap=12g}"
     # crates/Cross.toml injects the arm64 dev libs into the image (the daemon's
     # set; the Qt desktop is not cross-built, see build-aarch64-linux.sh).
+    # cross mounts CARGO_TARGET_DIR into the container: the worktree's own
+    # target here too, never one another worktree also builds into.
+    CARGO_TARGET_DIR="$(python3 scripts/qt-target.py resolve)"
+    export CARGO_TARGET_DIR
     ( cd crates && cross build --release --target "$TARGET" -p qbzd )
-    install -Dm755 "crates/target/$TARGET/release/qbzd" "$OUT"
+    install -Dm755 "$CARGO_TARGET_DIR/$TARGET/release/qbzd" "$OUT"
     ;;
   *)
     echo "[qbzd-aarch64] ERROR: unsupported build host arch: $arch" >&2

scripts/qbzd-acceptance.sh

@@ -31,7 +31,7 @@ fail() { echo "FAIL: $1" >&2; exit 1; }
 command -v curl    >/dev/null 2>&1 || fail "curl is required"
 command -v python3 >/dev/null 2>&1 || fail "python3 is required (status/ping/info shape checks)"
 command -v timeout  >/dev/null 2>&1 || fail "timeout (coreutils) is required"
-[ -x "$QBZD_BIN" ] || fail "qbzd binary not found/executable at $QBZD_BIN -- build it first (release, on its own: cargo build --release -p qbzd)"
+[ -x "$QBZD_BIN" ] || fail "qbzd binary not found/executable at $QBZD_BIN -- build it first (release, on its own, into this worktree's target: python3 scripts/qt-cargo.py build --release --manifest-path crates/Cargo.toml -p qbzd)"
 
 # ---------------------------------------------------------------------------
 # Isolated scratch profile root. NEVER the real daemon/desktop roots: dirs::

scripts/qml-tests/imports/com/blitzfc/qbz/QbzAlbum.qml

@@ -0,0 +1,7 @@
+pragma Singleton
+import QtQuick
+QtObject {
+    property var opened: []
+    function openAlbum(id) { opened = opened.concat([String(id)]) }
+    function openAlbumFrom(id, title, artist) { opened = opened.concat([String(id)]) }
+}

scripts/qml-tests/imports/com/blitzfc/qbz/QbzArtist.qml

@@ -0,0 +1,6 @@
+pragma Singleton
+import QtQuick
+QtObject {
+    property var opened: []
+    function openArtist(id) { opened = opened.concat([String(id)]) }
+}

scripts/qml-tests/imports/com/blitzfc/qbz/QbzHome.qml

@@ -0,0 +1,6 @@
+pragma Singleton
+import QtQuick
+QtObject {
+    property var labels: []
+    function openLabel(id) { labels = labels.concat([String(id)]) }
+}

scripts/qml-tests/imports/com/blitzfc/qbz/QbzLocal.qml

@@ -6,4 +6,18 @@ QtObject {
     property int pairingCancels: 0
     function mediaCancelQuickConnect() { pairingCancels++ }
     function mediaQuickConnect(url) {}
+
+    // Folder tree rail (LocalTreeRail / TreeRow).
+    property bool localTreeLoading: false
+    property int localTreeSelectedCount: 0
+    property var treeCalls: []
+    function treeToggleFolderSelect(path) { treeCalls = treeCalls.concat(["folder:" + path]) }
+    function treeToggleTrackSelect(path) { treeCalls = treeCalls.concat(["track:" + path]) }
+    function treeSelectRange(json) { treeCalls = treeCalls.concat(["range:" + json]) }
+    function treeToggle(path, open) {}
+    function treeCollapseAll() {}
+    function treeSearch(query) {}
+    function foldersBulkAction(action) {}
+    function playFolder(path) {}
+    function enqueue(kind, id, mode) {}
 }

scripts/qml-tests/imports/com/blitzfc/qbz/QbzMyQbz.qml

@@ -0,0 +1,14 @@
+pragma Singleton
+import QtQuick
+QtObject {
+    property var selectCalls: []
+    property var opened: []
+    property var played: []
+    function detailToggleItemSelect(position, shift) {
+        selectCalls = selectCalls.concat([{ "position": position, "shift": shift }])
+    }
+    function openItem(source, itemType, id) { opened = opened.concat([String(id)]) }
+    function openArtist(source, name, id) { opened = opened.concat(["artist:" + name]) }
+    function playItem(id) { played = played.concat([String(id)]) }
+    function detailToggleRowExpand(id) {}
+}

scripts/qml-tests/imports/com/blitzfc/qbz/QbzSearch.qml

@@ -0,0 +1,6 @@
+pragma Singleton
+import QtQuick
+QtObject {
+    property var submitted: []
+    function searchSubmit(text) { submitted = submitted.concat([String(text)]) }
+}

scripts/qml-tests/imports/com/blitzfc/qbz/qmldir

@@ -9,3 +9,8 @@ singleton QbzPurchases 1.0 QbzPurchases.qml
 singleton QbzOrbit 1.0 QbzOrbit.qml
 
 singleton QbzAbout 1.0 QbzAbout.qml
+singleton QbzArtist 1.0 QbzArtist.qml
+singleton QbzAlbum 1.0 QbzAlbum.qml
+singleton QbzSearch 1.0 QbzSearch.qml
+singleton QbzHome 1.0 QbzHome.qml
+singleton QbzMyQbz 1.0 QbzMyQbz.qml

scripts/qml-tests/tst_multi_select.qml

@@ -0,0 +1,455 @@
+// Excel-style multi-select regression suite: the shared selection rule
+// (controls/SelectionModel.qml) and the REAL row, card, checkbox and rail
+// components of the select-mode surfaces. Every click target a select-mode
+// surface offers must deliver Shift (a range from the anchor) and Ctrl (one
+// more row) to the selection; a target that swallows the modifier, or that
+// navigates away instead of selecting, is exactly the regression this guards.
+import QtQuick
+import QtTest
+import com.blitzfc.qbz
+import "../../crates/qbz-qt/qml/controls"
+import "../../crates/qbz-qt/qml/rows"
+import "../../crates/qbz-qt/qml/cards"
+import "../../crates/qbz-qt/qml/views" as Views
+import "../../crates/qbz-qt/qml/views/local" as Local
+import "../../crates/qbz-qt/qml/views/myqbz" as MyQbz
+import "../../crates/qbz-qt/qml/settings" as Settings
+
+Item {
+    id: root
+    width: 1200; height: 1400
+
+    function track(i) {
+        return { "id": "t" + i, "title": "Track " + i, "artist": "Artist " + i,
+                 "artistId": "a" + i, "album": "Album " + i, "albumId": "al" + i,
+                 "duration": "3:00", "qualityTier": "", "qualityDetail": "" }
+    }
+    function album(i) {
+        return { "id": "b" + i, "title": "Record " + i, "artist": "Band " + i,
+                 "artistId": "band" + i, "label": "Label " + i, "labelId": "l" + i,
+                 "year": "2001", "qualityTier": "", "qualityDetail": "" }
+    }
+    function range(n, make) {
+        var out = []
+        for (var i = 0; i < n; i++)
+            out.push(make(i))
+        return out
+    }
+
+    // ---- the track list (AlbumView / PlaylistView wiring) -------------------
+    property var tracks: range(8, track)
+    property var trackSelected: ({})
+    SelectionModel { id: trackSel }
+    function toggleTrack(id, mods) {
+        root.trackSelected = trackSel.next(root.trackSelected, id, root.tracks,
+                                           mods === undefined ? Qt.NoModifier : mods)
+    }
+
+    Column {
+        id: trackColumn
+        width: 1000
+        Repeater {
+            id: trackRepeater
+            model: root.tracks
+            delegate: TrackRow {
+                required property var modelData
+                required property int index
+                width: 1000
+                item: modelData
+                number: index + 1
+                artistLink: true
+                showAlbum: true
+                selectMode: true
+                checked: root.trackSelected[modelData.id] === true
+                onToggleSelect: function (mods) { root.toggleTrack(modelData.id, mods) }
+            }
+        }
+    }
+
+    // ---- the album list (Library albums list wiring) ------------------------
+    property var albums: range(6, album)
+    property var albumSelected: ({})
+    SelectionModel { id: albumSel }
+    function toggleAlbum(id, mods) {
+        root.albumSelected = albumSel.next(root.albumSelected, id, root.albums,
+                                           mods === undefined ? Qt.NoModifier : mods)
+    }
+
+    Column {
+        id: albumColumn
+        y: 420
+        width: 1000
+        Repeater {
+            id: albumRepeater
+            model: root.albums
+            delegate: Views.AlbumListRow {
+                required property var modelData
+                required property int index
+                width: 1000
+                item: modelData
+                rowIndex: index
+                selectMode: true
+                checked: root.albumSelected[modelData.id] === true
+                onToggleSelect: function (mods) { root.toggleAlbum(modelData.id, mods) }
+            }
+        }
+    }
+
+    // ---- one album card and the two checkbox controls ------------------------
+    property var cardMods: []
+    AlbumCard {
+        id: card
+        x: 1000; y: 0
+        albumId: "card"
+        title: "Card title"
+        artist: "Card artist"
+        artistId: "card-artist"
+        selectMode: true
+        onSelectToggled: function (mods) { root.cardMods = root.cardMods.concat([mods]) }
+    }
+
+    property var checkboxMods: []
+    QbzCheckbox {
+        id: checkbox
+        x: 1000; y: 320
+        onToggled: function (mods) { root.checkboxMods = root.checkboxMods.concat([mods]) }
+    }
+    property var selectCheckMods: []
+    Local.SelectCheck {
+        id: selectCheck
+        x: 1040; y: 320
+        onToggled: function (mods) { root.selectCheckMods = root.selectCheckMods.concat([mods]) }
+    }
+
+    // ---- a My QBZ collection row (selection lives in Rust) ----------------------
+    MyQbz.MyQbzDetailRow {
+        id: myqbzRow
+        x: 0; y: 820
+        width: 1000
+        selectMode: true
+        item: ({ "position": 3, "itemType": "album", "source": "qobuz",
+                 "sourceItemId": "alb3", "title": "Collected record", "subtitle": "Collected band",
+                 "subtitleIsLink": true, "artistId": "cb" })
+    }
+
+    // ---- the Local Library folder rail (selection lives in Rust) ----------------
+    QtObject {
+        id: railView
+        property bool treeSelectMode: true
+        property string selectedFolder: ""
+        property string treeSearch: ""
+        property bool skelPhase: false
+        property var opened: []
+        property var tree: [
+            { "path": "/m/a", "segment": "a", "depth": 0, "isFolder": true, "canExpand": true },
+            { "path": "/m/a/1.flac", "segment": "1.flac", "depth": 1, "isFolder": false },
+            { "path": "/m/b", "segment": "b", "depth": 0, "isFolder": true, "canExpand": true },
+            { "path": "/m/c", "segment": "c", "depth": 0, "isFolder": true, "canExpand": true },
+            { "path": "/m/d", "segment": "d", "depth": 0, "isFolder": true, "canExpand": true }
+        ]
+        function toggleTreeSelectMode() { treeSelectMode = !treeSelectMode }
+        function selectFolder(path) { opened = opened.concat([path]) }
+    }
+    Local.LocalTreeRail {
+        id: rail
+        x: 1000; y: 400
+        width: 200; height: 400
+        view: railView
+    }
+
+    // ---- Settings > Local Library folders ---------------------------------------
+    Settings.LibraryFolderTable {
+        id: folderTable
+        x: 0; y: 880
+        width: 1200
+        lib: ({ "folders": [1, 2, 3, 4, 5].map(function (n) {
+            return { "id": n, "displayName": "Music " + n, "path": "/music/" + n,
+                     "isNetwork": false, "enabled": true, "accessible": true,
+                     "status": "active", "lastScan": 0 }
+        }) })
+    }
+
+    TestCase {
+        name: "MultiSelect"
+        when: windowShown
+
+        function find(item, pred) {
+            if (!item)
+                return null
+            if (pred(item))
+                return item
+            var kids = item.children || []
+            for (var i = 0; i < kids.length; i++) {
+                var hit = find(kids[i], pred)
+                if (hit)
+                    return hit
+            }
+            return null
+        }
+        function shown(item) {
+            for (var it = item; it; it = it.parent)
+                if (!it.visible)
+                    return false
+            return true
+        }
+        function textItem(host, text) {
+            var t = find(host, function (it) {
+                return it.text === text && it.contentWidth !== undefined && shown(it)
+            })
+            verify(t !== null, "text '" + text + "' is drawn")
+            return t
+        }
+        // Clicks go through the window at the item's position, so whichever
+        // MouseArea really sits on top there receives them — the point of
+        // using the real components.
+        function clickOn(item, x, y, mods) {
+            var p = item.mapToItem(root, x, y)
+            mouseClick(root, p.x, p.y, Qt.LeftButton, mods === undefined ? Qt.NoModifier : mods)
+            wait(20)
+        }
+        function selectedIds(map) {
+            return Object.keys(map).sort().join(",")
+        }
+        function trackRow(i) { return trackRepeater.itemAt(i) }
+        function albumRow(i) { return albumRepeater.itemAt(i) }
+        function disc(row) {
+            var d = find(row, function (it) {
+                return it.width === 14 && it.height === 14 && it.hoverEnabled !== undefined
+                    && it.cursorShape !== undefined && shown(it)
+            })
+            verify(d !== null, "the select-mode disc is drawn")
+            return d
+        }
+
+        function init() {
+            root.trackSelected = ({})
+            trackSel.anchorId = ""
+            root.albumSelected = ({})
+            albumSel.anchorId = ""
+            root.cardMods = []
+            root.checkboxMods = []
+            root.selectCheckMods = []
+            QbzArtist.opened = []
+            QbzAlbum.opened = []
+            QbzHome.labels = []
+            QbzMyQbz.selectCalls = []
+            QbzMyQbz.opened = []
+            QbzMyQbz.played = []
+            QbzLocal.treeCalls = []
+            railView.opened = []
+            railView.treeSelectMode = true
+            folderTable.selectedIds = []
+        }
+
+        // A point of the row with nothing drawn over it but the body: the
+        // duration cell.
+        function bodyPoint(row) {
+            var duration = textItem(row, "3:00")
+            return duration.mapToItem(row, duration.width / 2, duration.height / 2)
+        }
+        function clickBody(row, mods) {
+            var p = bodyPoint(row)
+            clickOn(row, p.x, p.y, mods)
+        }
+
+        function test_row_body_shift_and_ctrl() {
+            clickBody(trackRow(1))
+            clickBody(trackRow(4), Qt.ShiftModifier)
+            compare(selectedIds(root.trackSelected), "t1,t2,t3,t4")
+            clickBody(trackRow(6), Qt.ControlModifier)
+            compare(selectedIds(root.trackSelected), "t1,t2,t3,t4,t6")
+        }
+
+        function test_checkbox_disc_shift_and_ctrl() {
+            clickOn(disc(trackRow(0)), 7, 7)
+            clickOn(disc(trackRow(3)), 7, 7, Qt.ShiftModifier)
+            compare(selectedIds(root.trackSelected), "t0,t1,t2,t3",
+                    "Shift on the disc selects the range")
+            clickOn(disc(trackRow(5)), 7, 7, Qt.ControlModifier)
+            clickOn(disc(trackRow(7)), 7, 7, Qt.ControlModifier | Qt.ShiftModifier)
+            compare(selectedIds(root.trackSelected), "t0,t1,t2,t3,t5,t6,t7",
+                    "Ctrl adds a row and Ctrl+Shift adds a second group")
+        }
+
+        function test_artist_link_selects_in_select_mode() {
+            clickBody(trackRow(2))
+            var name = textItem(trackRow(5), "Artist 5")
+            clickOn(name, 10, name.height / 2, Qt.ShiftModifier)
+            compare(QbzArtist.opened.length, 0, "no artist page opens in select mode")
+            compare(selectedIds(root.trackSelected), "t2,t3,t4,t5")
+        }
+
+        function test_album_link_selects_in_select_mode() {
+            var name = textItem(trackRow(6), "Album 6")
+            clickOn(name, 10, name.height / 2)
+            compare(QbzAlbum.opened.length, 0, "no album page opens in select mode")
+            compare(selectedIds(root.trackSelected), "t6")
+        }
+
+        function test_album_row_checkbox_shift_range() {
+            var first = find(albumRow(0), function (it) {
+                return it.checked !== undefined && it.width === 18 && it.height === 18 && shown(it)
+            })
+            var fourth = find(albumRow(3), function (it) {
+                return it.checked !== undefined && it.width === 18 && it.height === 18 && shown(it)
+            })
+            verify(first !== null && fourth !== null, "the album row checkboxes are drawn")
+            clickOn(first, 9, 9)
+            clickOn(fourth, 9, 9, Qt.ShiftModifier)
+            compare(selectedIds(root.albumSelected), "b0,b1,b2,b3")
+        }
+
+        function test_album_row_links_select_in_select_mode() {
+            clickOn(albumRow(1), 600, 32)
+            var band = textItem(albumRow(4), "Band 4")
+            clickOn(band, 10, band.height / 2, Qt.ShiftModifier)
+            compare(QbzArtist.opened.length, 0, "no artist page opens in select mode")
+            var label = textItem(albumRow(5), "Label 5")
+            clickOn(label, 10, label.height / 2, Qt.ControlModifier)
+            compare(QbzHome.labels.length, 0, "no label page opens in select mode")
+            compare(selectedIds(root.albumSelected), "b1,b2,b3,b4,b5")
+        }
+
+        function test_album_card_forwards_modifiers() {
+            clickOn(card, 100, 100, Qt.ShiftModifier)
+            var title = textItem(card, "Card title")
+            clickOn(title, 10, title.height / 2, Qt.ControlModifier)
+            var artist = textItem(card, "Card artist")
+            clickOn(artist, 10, artist.height / 2, Qt.ShiftModifier)
+            compare(QbzArtist.opened.length, 0, "no artist page opens in select mode")
+            compare(root.cardMods.length, 3)
+            verify((root.cardMods[0] & Qt.ShiftModifier) !== 0, "artwork carries Shift")
+            verify((root.cardMods[1] & Qt.ControlModifier) !== 0, "title carries Ctrl")
+            verify((root.cardMods[2] & Qt.ShiftModifier) !== 0, "artist line carries Shift")
+        }
+
+        function test_checkbox_controls_forward_modifiers() {
+            clickOn(checkbox, 9, 9, Qt.ShiftModifier)
+            clickOn(selectCheck, 6, 6, Qt.ControlModifier)
+            compare(root.checkboxMods.length, 1)
+            verify((root.checkboxMods[0] & Qt.ShiftModifier) !== 0, "QbzCheckbox carries Shift")
+            compare(root.selectCheckMods.length, 1)
+            verify((root.selectCheckMods[0] & Qt.ControlModifier) !== 0, "SelectCheck carries Ctrl")
+            checkbox.forceActiveFocus()
+            keyClick(Qt.Key_Space)
+            compare(root.checkboxMods.length, 2)
+            compare(root.checkboxMods[1] & Qt.ShiftModifier, 0, "the keyboard toggle is a plain toggle")
+        }
+
+        function test_myqbz_row_targets_select_with_shift() {
+            var title = textItem(myqbzRow, "Collected record")
+            clickOn(title, 10, title.height / 2)
+            var subtitle = textItem(myqbzRow, "Collected band")
+            clickOn(subtitle, 10, subtitle.height / 2, Qt.ShiftModifier)
+            compare(QbzMyQbz.opened.length, 0, "nothing opens in select mode")
+            compare(QbzMyQbz.selectCalls.length, 2)
+            compare(QbzMyQbz.selectCalls[0].position, 3)
+            compare(QbzMyQbz.selectCalls[0].shift, false)
+            compare(QbzMyQbz.selectCalls[1].shift, true, "Shift reaches the Rust range")
+        }
+
+        function railRow(path) {
+            var list = find(rail, function (it) { return it.model !== undefined && it.itemAtIndex !== undefined })
+            verify(list !== null, "the rail list exists")
+            for (var i = 0; i < railView.tree.length; i++)
+                if (railView.tree[i].path === path)
+                    return list.itemAtIndex(i)
+            return null
+        }
+        function railCheck(path) {
+            var row = railRow(path)
+            verify(row !== null, "rail row " + path + " is drawn")
+            var check = find(row, function (it) {
+                return it.partial !== undefined && it.on !== undefined && shown(it)
+            })
+            verify(check !== null, "rail checkbox " + path + " is drawn")
+            return check
+        }
+
+        function test_folder_rail_shift_range_and_modifier_body_click() {
+            tryVerify(function () { return railRow("/m/d") !== null }, 2000)
+            clickOn(railCheck("/m/a"), 6, 6)
+            clickOn(railCheck("/m/c"), 6, 6, Qt.ShiftModifier)
+            compare(QbzLocal.treeCalls.length, 2)
+            compare(QbzLocal.treeCalls[0], "folder:/m/a")
+            var range = JSON.parse(QbzLocal.treeCalls[1].slice("range:".length))
+            compare(range.map(function (n) { return n.path }).join(","), "/m/a,/m/a/1.flac,/m/b,/m/c")
+            compare(range[1].isFolder, false)
+            // A Ctrl click on a row body selects instead of opening the folder.
+            var d = railRow("/m/d")
+            clickOn(d, d.width - 20, d.height / 2, Qt.ControlModifier)
+            compare(QbzLocal.treeCalls[2], "folder:/m/d")
+            compare(railView.opened.length, 0)
+            // A plain click on the body still opens it.
+            clickOn(d, d.width - 20, d.height / 2)
+            compare(railView.opened.length, 1)
+            // Leaving select mode forgets the anchor: Shift is a plain toggle.
+            railView.treeSelectMode = false
+            railView.treeSelectMode = true
+            wait(0)
+            clickOn(railCheck("/m/b"), 6, 6, Qt.ShiftModifier)
+            compare(QbzLocal.treeCalls[3], "folder:/m/b")
+        }
+
+        function test_settings_folder_table_shift_range() {
+            var first = textItem(folderTable, "Music 1")
+            clickOn(first, 10, first.height / 2)
+            var fourth = textItem(folderTable, "Music 4")
+            clickOn(fourth, 10, fourth.height / 2, Qt.ShiftModifier)
+            compare(folderTable.selectedIds.slice().sort().join(","), "1,2,3,4")
+            verify(folderTable.isSelected(2), "the numeric ids stay numbers")
+        }
+    }
+
+    // ---- the selection rule itself ---------------------------------------------
+    SelectionModel { id: rule }
+    SelectionModel { id: keyedRule; idKey: "trackId" }
+    TestCase {
+        name: "SelectionRule"
+
+        function init() {
+            rule.anchorId = ""
+            keyedRule.anchorId = ""
+        }
+
+        function test_numeric_ids_range() {
+            var rows = [{ "id": 11 }, { "id": 12 }, { "id": 13 }, { "id": 14 }]
+            var m = rule.next({}, 11, rows, Qt.NoModifier)
+            m = rule.next(m, 13, rows, Qt.ShiftModifier)
+            compare(Object.keys(m).sort().join(","), "11,12,13")
+        }
+
+        function test_rows_without_id_are_skipped() {
+            var rows = [{ "id": "a" }, { "kind": "header" }, { "id": "b" }]
+            var m = rule.next({}, "a", rows, Qt.NoModifier)
+            m = rule.next(m, "b", rows, Qt.ShiftModifier)
+            compare(Object.keys(m).sort().join(","), "a,b")
+        }
+
+        function test_id_key() {
+            var rows = [{ "trackId": 7 }, { "trackId": 8 }, { "trackId": 9 }]
+            var m = keyedRule.next({}, 9, rows, Qt.NoModifier)
+            m = keyedRule.next(m, 7, rows, Qt.ShiftModifier)
+            compare(Object.keys(m).sort().join(","), "7,8,9")
+        }
+
+        function test_exclusive_rule() {
+            var rows = [{ "id": "g1" }, { "id": "g2" }, { "id": "g3" }, { "id": "g4" }, { "id": "g5" }]
+            var m = rule.nextExclusive({}, "g2", rows, Qt.NoModifier)
+            compare(Object.keys(m).sort().join(","), "g2", "a plain click selects only that row")
+            m = rule.nextExclusive(m, "g4", rows, Qt.ShiftModifier)
+            compare(Object.keys(m).sort().join(","), "g2,g3,g4", "Shift selects the range")
+            m = rule.nextExclusive(m, "g1", rows, Qt.ShiftModifier)
+            compare(Object.keys(m).sort().join(","), "g1,g2", "the anchor stays, Shift replaces the range")
+            m = rule.nextExclusive(m, "g5", rows, Qt.ControlModifier)
+            compare(Object.keys(m).sort().join(","), "g1,g2,g5", "Ctrl adds one")
+            m = rule.nextExclusive(m, "g5", rows, Qt.ControlModifier)
+            compare(Object.keys(m).sort().join(","), "g1,g2", "Ctrl on a selected row removes it")
+            m = rule.nextExclusive(m, "g3", rows, Qt.ControlModifier)
+            m = rule.nextExclusive(m, "g5", rows, Qt.ControlModifier | Qt.ShiftModifier)
+            compare(Object.keys(m).sort().join(","), "g1,g2,g3,g4,g5", "Ctrl+Shift adds a range")
+            m = rule.nextExclusive(m, "g4", rows, Qt.NoModifier)
+            compare(Object.keys(m).sort().join(","), "g4", "a plain click starts over")
+        }
+    }
+}

scripts/qt-cargo.py

@@ -12,9 +12,15 @@ Use this entry point for Qt builds/tests, including direct Cargo invocations:
 No target cleanup, profile changes, or RUSTFLAGS: a content-derived, unused
 C++ define invalidates cc-rs consumers when the SDK changes, in either profile
 and with any Rust toolchain. Existing CXXFLAGS (including MSVC flags) survive.
+
+Where Cargo builds follows scripts/qt-target.py: a host-level target shared by
+every worktree becomes this worktree's own sibling of it, so a direct build or
+test here cannot replace a binary another worktree built. An explicit
+CARGO_TARGET_DIR, or a target inside the checkout, is left to Cargo.
 """
 
 import hashlib
+import importlib.util
 import os
 from pathlib import Path
 import re
@@ -112,12 +118,56 @@ def cargo_environment(env):
     return result, version, fingerprint
 
 
+def load_targets():
+    # A hyphenated sibling loaded by path: without this, every build would leave
+    # an untracked scripts/__pycache__ in the checkout.
+    sys.dont_write_bytecode = True
+    spec = importlib.util.spec_from_file_location(
+        "qt_target", Path(__file__).with_name("qt-target.py"))
+    module = importlib.util.module_from_spec(spec)
+    spec.loader.exec_module(module)
+    return module
+
+
+def manifest_argument(arguments):
+    for index, argument in enumerate(arguments):
+        if argument == "--manifest-path" and index + 1 < len(arguments):
+            return Path(arguments[index + 1])
+        if argument.startswith("--manifest-path="):
+            return Path(argument.split("=", 1)[1])
+    return None
+
+
+def target_environment(env, arguments, targets=None):
+    """`env` with CARGO_TARGET_DIR set to this worktree's own target, when the
+    target Cargo would use is shared with other worktrees (qt-target.py)."""
+    targets = targets or load_targets()
+    if targets.explicit(env):
+        return env
+    try:
+        metadata = targets.cargo_metadata(manifest_argument(arguments), dict(env))
+        configured = Path(metadata["target_directory"]).resolve()
+        target = targets.worktree_target(
+            configured, targets.worktree_root(metadata["workspace_root"]), env)
+    except (OSError, subprocess.SubprocessError, KeyError, ValueError) as error:
+        print(f"[qt-cargo] target not resolved ({error}); Cargo's own choice stands",
+              file=sys.stderr, flush=True)
+        return env
+    if target == configured:
+        return env
+    result = dict(env)
+    result["CARGO_TARGET_DIR"] = str(target)
+    print(f"[qt-cargo] worktree target {target}", file=sys.stderr, flush=True)
+    return result
+
+
 def main():
     if len(sys.argv) < 2:
         raise RuntimeError("usage: qt-cargo.py <cargo subcommand> [arguments...]")
     env, version, fingerprint = cargo_environment(os.environ)
     print(f"[qt-cargo] Qt {version}, SDK {fingerprint}, qmake={env['QMAKE']}",
           file=sys.stderr, flush=True)
+    env = target_environment(env, sys.argv[2:])
     # subprocess.run, NOT os.execvpe: on Windows os.exec* is emulated (spawn +
     # terminate) and segfaulted here — the release-windows build died with
     # "Segmentation fault ... exit code 139" right after this line on

scripts/qt-run.sh

@@ -33,6 +33,16 @@
 # run BEFORE the build — failing in one second beats failing after two minutes,
 # or worse, at the owner's smoke. NO_AUDIT=1 skips them.
 #
+# ─── EACH WORKTREE BUILDS IN ITS OWN TARGET ─────────────────────────────────
+# scripts/qt-target.py decides where. With Cargo's default target (inside the
+# checkout: macOS, CI) nothing changes. When the host configures ONE target
+# outside the checkout for every worktree, this worktree builds in its own
+# sibling of it, `<target>-worktrees/<worktree>`, so a build in another worktree
+# can never replace the binary built here; rebuilding THIS worktree still does.
+# Its first build of a profile is seeded from the shared target with
+# copy-on-write clones, and crates/target is re-pointed after each successful
+# build. An explicit CARGO_TARGET_DIR is used exactly as given.
+#
 # Usage: ./scripts/qt-run.sh [extra app args]
 #   DEBUG=1     ./scripts/qt-run.sh   # debug profile (the binary the gate uses)
 #   NORUN=1     ./scripts/qt-run.sh   # build only, don't exec
@@ -127,7 +137,6 @@ if [[ "${DEBUG:-0}" == 1 ]]; then
 else
   PROFILE=release; PROFILE_ARGS=(--release)
 fi
-BIN="${CARGO_TARGET_DIR:-crates/target}/${PROFILE}/qbz"
 
 # --- ONE BUILD AT A TIME, BOX-WIDE ------------------------------------------
 # Not paranoia: a Slint `qbz-ui` rustc in another worktree peaks 20-30 GB on a
@@ -141,6 +150,13 @@ if [[ "${FORCE:-0}" != 1 ]]; then
   fi
 fi
 
+# --- Where this worktree builds (see the header) -----------------------------
+# The PHYSICAL path: moc/cc-rs resolve includes wrongly through the crates/target
+# symlink.
+CARGO_TARGET_DIR="$(python3 scripts/qt-target.py resolve)" || die "could not resolve the Cargo target directory"
+export CARGO_TARGET_DIR
+BIN="${CARGO_TARGET_DIR}/${PROFILE}/qbz"
+
 # --- The QML audits (fail fast; cargo cannot see QML) ------------------------
 if [[ "${NO_AUDIT:-0}" != 1 ]]; then
   if [[ -d "${AUDIT_DIR}" ]] && command -v python3 >/dev/null 2>&1; then
@@ -198,6 +214,17 @@ eta_secs=0
 
 avail_mb=$(mem_avail_mb)
 say "profile=${PROFILE} jobs=${CARGO_BUILD_JOBS} avail=${avail_mb}MB rustflags='${RUSTFLAGS:-}'"
+say "target=${CARGO_TARGET_DIR}"
+
+# A worktree target's first build of a profile starts from the shared target's
+# artifacts (copy-on-write, nothing duplicated) instead of from nothing. After
+# the one-build guard on purpose: never clone a target another build is writing.
+seed_profiles=("${PROFILE}")
+[[ "${TEST:-0}" == 1 && "${PROFILE}" != debug ]] && seed_profiles+=(debug)
+if [[ -z "$(other_builds)" ]]; then
+  python3 scripts/qt-target.py seed --target-dir "${CARGO_TARGET_DIR}" "${seed_profiles[@]}" \
+    || warn "could not seed ${CARGO_TARGET_DIR}; Cargo builds it from scratch"
+fi
 
 # --- Start banner ------------------------------------------------------------
 build_start=$(date +%s)
@@ -232,6 +259,11 @@ fi
 # --- The build ---------------------------------------------------------------
 python3 scripts/qt-cargo.py build "${PROFILE_ARGS[@]}" --manifest-path crates/Cargo.toml -p qbz-qt
 
+# The familiar crates/target path follows the target this worktree just built,
+# and only after a successful build.
+python3 scripts/qt-target.py link --target-dir "${CARGO_TARGET_DIR}" \
+  || warn "crates/target was not re-pointed; the binary is ${BIN}"
+
 # --- Stop the ticker, record the duration, print the final banner ------------
 [[ -n "${tick_pid}" ]] && { kill "${tick_pid}" 2>/dev/null || true; wait "${tick_pid}" 2>/dev/null || true; }
 trap - EXIT
@@ -239,6 +271,7 @@ build_secs=$(( $(date +%s) - build_start ))
 mkdir -p "${eta_dir}" 2>/dev/null && printf '%s\n' "${build_secs}" > "${eta_file}" 2>/dev/null || true
 printf '%s[qt-run] ✔ build finished %s  ·  took %s  (%s)%s\n' \
   "${C_BOLD}${C_GRN}" "$(date '+%H:%M:%S')" "$(fmt_dur "${build_secs}")" "${PROFILE}" "${C_RST}"
+say "binary=${BIN}"
 
 # --- Tests (opt-in) ----------------------------------------------------------
 if [[ "${TEST:-0}" == 1 ]]; then
@@ -260,7 +293,7 @@ if [[ "${SMOKE:-0}" == 1 ]]; then
   # template path so the two agree.
   log="$(mktemp "${TMPDIR:-/tmp}/qbz-qt-smoke-XXXXXX")"
   say "offscreen smoke (75s max) → ${log}"
-  QT_QPA_PLATFORM=offscreen RUST_LOG=info run_timeout 75 "./${BIN}" > "${log}" 2>&1 || true
+  QT_QPA_PLATFORM=offscreen RUST_LOG=info run_timeout 75 "${BIN}" > "${log}" 2>&1 || true
   # A log this short means the process never really started (the macOS
   # `timeout`-not-found case did exactly that). Zero complaints in an empty log
   # is not a pass.

scripts/qt-runtime-gate.sh

@@ -3,6 +3,10 @@
 set -euo pipefail
 cd "$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)/.."
 export QBZ_PREBUILT_SHADERS=1
+# The same target qt-run.sh builds in: this worktree's own when the host shares
+# one target across worktrees, Cargo's default otherwise (scripts/qt-target.py).
+CARGO_TARGET_DIR="$(python3 scripts/qt-target.py resolve)"
+export CARGO_TARGET_DIR
 bash scripts/test-search-local-qml.sh
 bash scripts/test-updates-qml.sh
 bash scripts/test-playback-cache-qml.sh
@@ -11,6 +15,7 @@ bash scripts/test-compact-seek-qml.sh
 bash scripts/test-library-folders-qml.sh
 bash scripts/test-array-model-qml.sh
 bash scripts/test-keyed-model-qml.sh
+bash scripts/test-multi-select-qml.sh
 bash scripts/test-wallpaper-field-qml.sh
 bash scripts/test-card-menu-qml.sh
 bash scripts/test-orbit-qml.sh
@@ -22,7 +27,7 @@ node scripts/test_qt_kiosk_navigation.mjs
 node scripts/test_qt_kiosk_feedback.mjs
 node scripts/test_qt_exclusive_gate.mjs
 python3 scripts/qt-cargo.py test --manifest-path crates/Cargo.toml -p qbz-qt --no-fail-fast
-target_dir="${CARGO_TARGET_DIR:-$PWD/crates/target}"
+target_dir="$CARGO_TARGET_DIR"
 logs="$(mktemp -d "${TMPDIR:-/tmp}/qbz-qt-gate-XXXXXX")"
 printf '[qt-gate] startup logs: %s\n' "$logs"
 for profile in debug release; do
@@ -31,5 +36,7 @@ for profile in debug release; do
   python3 scripts/qt-cargo.py build "${args[@]}" --manifest-path crates/Cargo.toml -p qbz-qt
   python3 scripts/qt-smoke.py "$target_dir/$profile/qbz" --log "$logs/$profile.log"
 done
+python3 scripts/qt-target.py link --target-dir "$target_dir" \
+  || printf '[qt-gate] crates/target not re-pointed; binaries are in %s\n' "$target_dir" >&2
 # A healthy offscreen bus cannot expose Qt's synchronous xcb D-Bus startup.
 python3 scripts/qt-smoke.py "$target_dir/release/qbz" --silent-bus --log "$logs/release-silent-bus.log"

scripts/qt-target.py

@@ -0,0 +1,213 @@
+#!/usr/bin/env python3
+"""Each worktree's own physical Cargo target, and its crates/target shortcut.
+
+A host may put Cargo's target OUTSIDE the checkout, on a build disk shared by
+every worktree below one project directory. Then every worktree compiled into
+the SAME directory, and a build in any of them replaced the `qbz` binary another
+worktree had just built and was running or smoke-testing (2026-09-14: a parallel
+session's release build replaced the binary under test in the main worktree).
+
+So when the target Cargo resolves lies outside the worktree, and nobody pinned it
+explicitly with CARGO_TARGET_DIR or CARGO_BUILD_TARGET_DIR, the worktree builds
+in its own sibling directory instead:
+
+    <configured target>-worktrees/<worktree directory name>
+
+Building the same worktree again still replaces its own binary; other worktrees
+keep theirs. A target inside the checkout (Cargo's default: macOS, CI, Windows)
+and an explicit override are returned unchanged. No machine-specific path lives
+here: Cargo configuration and the environment choose the storage.
+
+The first build of a profile in a new worktree target is seeded from the shared
+target with copy-on-write clones (`cp --reflink=always`), so the registry crates
+that did not change are not compiled again and no data is duplicated; where the
+filesystem cannot clone, nothing is copied and Cargo simply builds from scratch.
+Never remove a real target directory to make room for a symlink.
+"""
+import argparse
+import hashlib
+import json
+import os
+from pathlib import Path
+import re
+import shutil
+import subprocess
+import sys
+import uuid
+
+EXPLICIT_ENV = ("CARGO_TARGET_DIR", "CARGO_BUILD_TARGET_DIR")
+MARKER = ".qbz-worktree"
+SUFFIX = "-worktrees"
+# Workspace crates recompile per worktree anyway (their metadata hash includes
+# the checkout path), and incremental caches are only kept for those.
+SEED_SKIP = {"incremental"}
+
+
+def cargo_metadata(manifest=None, env=None):
+    command = ["cargo", "metadata", "--no-deps", "--format-version", "1"]
+    if manifest is not None:
+        command += ["--manifest-path", str(manifest)]
+    return json.loads(subprocess.check_output(command, text=True, env=env))
+
+
+def worktree_root(workspace_root):
+    workspace_root = Path(workspace_root)
+    try:
+        top = subprocess.check_output(
+            ["git", "-C", str(workspace_root), "rev-parse", "--show-toplevel"],
+            text=True, stderr=subprocess.DEVNULL).strip()
+        if top:
+            return Path(top).resolve()
+    except (OSError, subprocess.SubprocessError):
+        pass
+    # This repository keeps its Cargo workspace in crates/.
+    return workspace_root.resolve().parent
+
+
+def is_inside(path, root):
+    try:
+        Path(path).relative_to(root)
+        return True
+    except ValueError:
+        return False
+
+
+def explicit(env):
+    return any(env.get(name) for name in EXPLICIT_ENV)
+
+
+def worktree_target(configured, root, env):
+    """The target this worktree builds in (see the module docstring)."""
+    configured = Path(configured).resolve()
+    root = Path(root).resolve()
+    if explicit(env) or is_inside(configured, root):
+        return configured
+    name = re.sub(r"[^A-Za-z0-9._-]+", "-", root.name).strip("-") or "worktree"
+    candidate = configured.parent / f"{configured.name}{SUFFIX}" / name
+    try:
+        claimed = (candidate / MARKER).read_text().strip()
+    except OSError:
+        claimed = ""
+    if claimed and claimed != str(root):
+        # Two checkouts with the same directory name: the second one gets a
+        # stable suffix instead of sharing (and overwriting) the first.
+        digest = hashlib.sha1(str(root).encode()).hexdigest()[:8]
+        candidate = candidate.with_name(f"{name}-{digest}")
+    return candidate
+
+
+def shared_target(manifest=None, env=None):
+    """Cargo's configured target with any explicit override removed."""
+    env = dict(os.environ if env is None else env)
+    for name in EXPLICIT_ENV:
+        env.pop(name, None)
+    return Path(cargo_metadata(manifest, env)["target_directory"]).resolve()
+
+
+def resolve_target(manifest=None, env=None):
+    env = os.environ if env is None else env
+    metadata = cargo_metadata(manifest, dict(env))
+    root = worktree_root(metadata["workspace_root"])
+    return worktree_target(metadata["target_directory"], root, env)
+
+
+def is_worktree_target(target, shared):
+    target = Path(target).resolve()
+    shared = Path(shared).resolve()
+    return target.parent == shared.parent / f"{shared.name}{SUFFIX}"
+
+
+def link_target(manifest, target, root=None):
+    target = Path(target).resolve()
+    alias = Path(manifest).resolve().parent / "target"
+    if not target.is_dir():
+        raise RuntimeError(f"build target does not exist: {target}")
+    if root is not None and target.parent.name.endswith(SUFFIX):
+        # Claim this worktree target for its checkout (see worktree_target).
+        (target / MARKER).write_text(f"{Path(root).resolve()}\n")
+    if alias.resolve() == target:
+        return
+    if alias.exists() and not alias.is_symlink():
+        raise RuntimeError(f"preserving existing target directory: {alias}; migrate it before linking")
+    if os.name == "nt":
+        # A normal Windows Cargo target already uses alias. External targets
+        # must remain usable without requiring symlink privileges in CI.
+        print(f"[qt-target] external target: {target} (shortcut not created on Windows)", file=sys.stderr)
+        return
+    temporary = alias.with_name(f".target-link-{uuid.uuid4().hex}")
+    try:
+        temporary.symlink_to(target, target_is_directory=True)
+        temporary.replace(alias)
+    finally:
+        temporary.unlink(missing_ok=True)
+
+
+def seed_target(target, shared, profiles, clone=None):
+    """Clone each missing profile directory of `shared` into `target`.
+
+    Returns the profiles seeded. A profile already present in `target`, absent
+    from `shared`, or that the filesystem cannot clone is left alone.
+    """
+    target = Path(target)
+    shared = Path(shared)
+    clone = clone or reflink_clone
+    seeded = []
+    if target.resolve() == shared.resolve() or not is_worktree_target(target, shared):
+        return seeded
+    for profile in profiles:
+        source = shared / profile
+        destination = target / profile
+        if destination.exists() or not source.is_dir():
+            continue
+        target.mkdir(parents=True, exist_ok=True)
+        staging = target / f".seed-{profile}-{uuid.uuid4().hex}"
+        staging.mkdir()
+        try:
+            entries = sorted(entry for entry in source.iterdir() if entry.name not in SEED_SKIP)
+            if entries:
+                clone(entries, staging)
+            # Appears whole or not at all: an interrupted clone never looks
+            # like a finished target to Cargo.
+            staging.rename(destination)
+            seeded.append(profile)
+        except (OSError, subprocess.SubprocessError) as error:
+            print(f"[qt-target] not seeding {profile} ({error}); Cargo builds it from scratch", file=sys.stderr)
+        finally:
+            if staging.exists():
+                shutil.rmtree(staging, ignore_errors=True)
+    return seeded
+
+
+def reflink_clone(entries, destination):
+    if not sys.platform.startswith("linux"):
+        raise OSError("copy-on-write clones are only used with GNU cp")
+    subprocess.run(["cp", "-a", "--reflink=always", *map(str, entries), str(destination)],
+                   check=True, stdout=subprocess.DEVNULL, stderr=subprocess.PIPE)
+
+
+def main():
+    parser = argparse.ArgumentParser(description=__doc__, formatter_class=argparse.RawDescriptionHelpFormatter)
+    parser.add_argument("operation", choices=["resolve", "link", "seed"])
+    parser.add_argument("profiles", nargs="*", help="seed: profile directories, e.g. release debug")
+    parser.add_argument("--manifest-path", default="crates/Cargo.toml", type=Path)
+    parser.add_argument("--target-dir", type=Path)
+    args = parser.parse_args()
+    if args.operation == "resolve":
+        print(args.target_dir.resolve() if args.target_dir else resolve_target(args.manifest_path))
+        return
+    target = args.target_dir.resolve() if args.target_dir else resolve_target(args.manifest_path)
+    if args.operation == "link":
+        root = worktree_root(Path(args.manifest_path).resolve().parent)
+        link_target(args.manifest_path, target, root)
+        return
+    shared = shared_target(args.manifest_path)
+    for profile in seed_target(target, shared, args.profiles or ["release"]):
+        print(f"[qt-target] seeded {profile} from {shared / profile}", file=sys.stderr)
+
+
+if __name__ == "__main__":
+    try:
+        main()
+    except (OSError, RuntimeError, subprocess.SubprocessError, KeyError, ValueError) as error:
+        print(f"[qt-target] {error}", file=sys.stderr)
+        sys.exit(1)

scripts/test-multi-select-qml.sh

@@ -0,0 +1,21 @@
+#!/usr/bin/env bash
+# Excel-style multi-select regression: every select-mode click target — row
+# body, checkbox disc, checkbox controls, album cards, the name links on a
+# row, the My QBZ rows, the folder rail and the settings folder table — hands
+# Shift / Ctrl to the selection rule, and the rule itself ranges over string
+# and numeric ids alike. Same run in CI and locally.
+set -euo pipefail
+cd "$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)/.."
+if [[ -n "${QT_ROOT_DIR:-}" ]]; then
+  qt_multi_select_bins="$QT_ROOT_DIR/bin"
+else
+  qt_multi_select_qmake="${QMAKE:-}"
+  if [[ -z "$qt_multi_select_qmake" ]]; then
+    qt_multi_select_qmake="$(command -v qmake6 || command -v qmake)"
+  fi
+  qt_multi_select_bins="$("$qt_multi_select_qmake" -query QT_INSTALL_BINS)"
+fi
+QT_QPA_PLATFORM=offscreen QT_QUICK_BACKEND=software \
+  "$qt_multi_select_bins/qmltestrunner" \
+  -input scripts/qml-tests/tst_multi_select.qml \
+  -import scripts/qml-tests/imports

scripts/test_qt_build_gates.py

@@ -1,9 +1,14 @@
 #!/usr/bin/env python3
 """SDK-cache and crash-aware smoke regressions; no Qt or Cargo build needed."""
 
+import contextlib
 import importlib.util
+import io
+import json
 import os
 from pathlib import Path
+import shutil
+import subprocess
 import tempfile
 import unittest
 import sys
@@ -21,6 +26,222 @@ def load(name, filename):
 
 qt = load("qt_cargo", "qt-cargo.py")
 smoke = load("qt_smoke", "qt-smoke.py")
+targets = load("qt_target", "qt-target.py")
+
+
+@unittest.skipIf(os.name == "nt", "unprivileged Windows symlinks may be unavailable")
+class TargetTests(unittest.TestCase):
+    """Each worktree keeps its own binaries when the host shares one target."""
+
+    def setUp(self):
+        self.temp = tempfile.TemporaryDirectory()
+        self.addCleanup(self.temp.cleanup)
+        self.root = Path(self.temp.name).resolve()
+        self.worktree = self.root / "checkouts" / "main-tree"
+        self.crates = self.worktree / "crates"
+        self.crates.mkdir(parents=True)
+        self.manifest = self.crates / "Cargo.toml"
+        self.manifest.touch()
+        self.shared = self.root / "nvme" / "qbz"
+        (self.shared / "release" / "deps").mkdir(parents=True)
+        (self.shared / "release" / "incremental").mkdir()
+        (self.shared / "release" / "deps" / "libdep.rlib").write_bytes(b"registry crate")
+        (self.shared / "release" / "incremental" / "session").write_bytes(b"workspace cache")
+        (self.shared / "release" / "qbz").write_bytes(b"another worktree's binary")
+        self.derived = self.root / "nvme" / "qbz-worktrees" / "main-tree"
+
+    def test_shared_host_target_becomes_this_worktrees_own_sibling(self):
+        self.assertEqual(targets.worktree_target(self.shared, self.worktree, {}), self.derived)
+        other = self.root / "checkouts" / "codex-tree"
+        self.assertEqual(targets.worktree_target(self.shared, other, {}),
+                         self.root / "nvme" / "qbz-worktrees" / "codex-tree")
+
+    def test_explicit_override_and_checkout_target_are_used_as_given(self):
+        for name in targets.EXPLICIT_ENV:
+            with self.subTest(env=name):
+                self.assertEqual(targets.worktree_target(self.shared, self.worktree, {name: "/pinned"}),
+                                 self.shared)
+        inside = self.crates / "target"
+        self.assertEqual(targets.worktree_target(inside, self.worktree, {}), inside)
+
+    def test_two_checkouts_with_one_directory_name_never_share_a_target(self):
+        self.derived.mkdir(parents=True)
+        (self.derived / targets.MARKER).write_text(str(self.root / "elsewhere" / "main-tree") + "\n")
+        second = targets.worktree_target(self.shared, self.worktree, {})
+        self.assertNotEqual(second, self.derived)
+        self.assertTrue(second.name.startswith("main-tree-"))
+        self.assertEqual(second, targets.worktree_target(self.shared, self.worktree, {}))
+        (self.derived / targets.MARKER).write_text(str(self.worktree) + "\n")
+        self.assertEqual(targets.worktree_target(self.shared, self.worktree, {}), self.derived)
+
+    def test_resolve_reads_cargo_metadata_for_the_manifest(self):
+        metadata = {"target_directory": str(self.shared), "workspace_root": str(self.crates)}
+        with patch.object(targets, "cargo_metadata", return_value=metadata) as cargo, \
+                patch.object(targets, "worktree_root", return_value=self.worktree):
+            self.assertEqual(targets.resolve_target(self.manifest, {}), self.derived)
+        self.assertEqual(cargo.call_args.args[0], self.manifest)
+
+    def test_link_keeps_the_familiar_path_and_claims_the_worktree_target(self):
+        (self.derived / "release").mkdir(parents=True)
+        (self.derived / "release" / "qbz").write_bytes(b"this worktree's binary")
+        targets.link_target(self.manifest, self.derived, self.worktree)
+        targets.link_target(self.manifest, self.derived, self.worktree)
+        alias = self.crates / "target"
+        self.assertTrue(alias.is_symlink())
+        self.assertEqual((alias / "release" / "qbz").read_bytes(), b"this worktree's binary")
+        self.assertEqual((self.derived / targets.MARKER).read_text().strip(), str(self.worktree))
+        # A pinned target is linked but never claimed.
+        targets.link_target(self.manifest, self.shared, self.worktree)
+        self.assertFalse((self.shared / targets.MARKER).exists())
+
+    def test_real_directory_is_never_removed(self):
+        alias = self.crates / "target"
+        alias.mkdir()
+        sentinel = alias / "keep"
+        sentinel.write_text("preserve")
+        targets.link_target(self.manifest, alias)
+        with self.assertRaisesRegex(RuntimeError, "preserving"):
+            targets.link_target(self.manifest, self.shared)
+        self.assertEqual(sentinel.read_text(), "preserve")
+        self.assertFalse(alias.is_symlink())
+
+    def test_old_shortcut_is_replaced_but_a_missing_build_cannot_replace_it(self):
+        alias = self.crates / "target"
+        alias.symlink_to(self.root / "old", target_is_directory=True)
+        with self.assertRaisesRegex(RuntimeError, "does not exist"):
+            targets.link_target(self.manifest, self.root / "missing")
+        self.assertEqual(os.readlink(alias), str(self.root / "old"))
+        targets.link_target(self.manifest, self.shared)
+        self.assertEqual(alias.resolve(), self.shared)
+
+    @staticmethod
+    def copy(entries, destination):
+        for entry in entries:
+            if entry.is_dir():
+                shutil.copytree(entry, destination / entry.name)
+            else:
+                shutil.copy2(entry, destination / entry.name)
+
+    def test_seed_clones_a_missing_profile_once_and_skips_incremental(self):
+        self.assertEqual(targets.seed_target(self.derived, self.shared, ["release", "debug"], self.copy),
+                         ["release"])
+        self.assertEqual((self.derived / "release" / "deps" / "libdep.rlib").read_bytes(), b"registry crate")
+        self.assertFalse((self.derived / "release" / "incremental").exists())
+        (self.derived / "release" / "qbz").write_bytes(b"this worktree's binary")
+        self.assertEqual(targets.seed_target(self.derived, self.shared, ["release"], self.copy), [])
+        self.assertEqual((self.derived / "release" / "qbz").read_bytes(), b"this worktree's binary")
+        self.assertEqual((self.shared / "release" / "qbz").read_bytes(), b"another worktree's binary")
+
+    def test_seed_never_touches_pinned_targets_and_leaves_no_partial_clone(self):
+        pinned = self.root / "pinned"
+        self.assertEqual(targets.seed_target(pinned, self.shared, ["release"], self.copy), [])
+        self.assertFalse(pinned.exists())
+        self.assertEqual(targets.seed_target(self.shared, self.shared, ["release"], self.copy), [])
+
+        def broken(entries, destination):
+            (destination / "half").write_bytes(b"partial")
+            raise OSError("clone not supported")
+
+        with contextlib.redirect_stderr(io.StringIO()):
+            self.assertEqual(targets.seed_target(self.derived, self.shared, ["release"], broken), [])
+        self.assertEqual(list(self.derived.iterdir()), [])
+
+
+class CargoTargetEnvironmentTests(unittest.TestCase):
+    def setUp(self):
+        self.temp = tempfile.TemporaryDirectory()
+        self.addCleanup(self.temp.cleanup)
+        self.root = Path(self.temp.name).resolve()
+        self.worktree = self.root / "tree"
+        self.shared = self.root / "shared" / "qbz"
+        self.metadata = {"target_directory": str(self.shared), "workspace_root": str(self.worktree / "crates")}
+        for name, value in (("cargo_metadata", lambda *_: self.metadata),
+                            ("worktree_root", lambda *_: self.worktree)):
+            mock = patch.object(targets, name, side_effect=value)
+            mock.start()
+            self.addCleanup(mock.stop)
+
+    def environment(self, env, arguments=("--manifest-path", "crates/Cargo.toml")):
+        with contextlib.redirect_stderr(io.StringIO()):
+            return qt.target_environment(env, list(arguments), targets)
+
+    def test_direct_builds_and_tests_use_the_worktree_target(self):
+        env = self.environment({"PATH": "/bin"})
+        self.assertEqual(env["CARGO_TARGET_DIR"], str(self.root / "shared" / "qbz-worktrees" / "tree"))
+        self.assertEqual(targets.cargo_metadata.call_args.args[0], Path("crates/Cargo.toml"))
+
+    def test_explicit_and_checkout_targets_are_left_to_cargo(self):
+        pinned = {"CARGO_TARGET_DIR": "/pinned"}
+        self.assertIs(self.environment(pinned), pinned)
+        self.metadata["target_directory"] = str(self.worktree / "crates" / "target")
+        plain = {"PATH": "/bin"}
+        self.assertIs(self.environment(plain), plain)
+
+    def test_unresolvable_metadata_keeps_cargos_own_choice(self):
+        targets.cargo_metadata.side_effect = subprocess.CalledProcessError(101, "cargo")
+        plain = {"PATH": "/bin"}
+        self.assertIs(self.environment(plain), plain)
+
+    def test_manifest_argument_forms(self):
+        self.assertEqual(qt.manifest_argument(["-p", "qbz-qt", "--manifest-path", "a/Cargo.toml"]),
+                         Path("a/Cargo.toml"))
+        self.assertEqual(qt.manifest_argument(["--manifest-path=b/Cargo.toml"]), Path("b/Cargo.toml"))
+        self.assertIsNone(qt.manifest_argument(["--release"]))
+
+
+@unittest.skipUnless(os.name == "posix" and shutil.which("bash"), "requires bash")
+class RunnerTargetTests(unittest.TestCase):
+    def test_runner_builds_in_the_worktree_target_links_after_success_and_runs_it(self):
+        with tempfile.TemporaryDirectory() as directory:
+            base = Path(directory).resolve()
+            root = base / "main tree"
+            scripts = root / "scripts"
+            scripts.mkdir(parents=True)
+            (root / "crates").mkdir()
+            (root / "crates/Cargo.toml").touch()
+            shared = base / "shared target"
+            expected = base / "shared target-worktrees" / "main-tree"
+            for filename in ("qt-run.sh", "qt-target.py"):
+                shutil.copyfile(Path(__file__).with_name(filename), scripts / filename)
+            fake_bin = base / "bin"
+            fake_bin.mkdir()
+            cargo = fake_bin / "cargo"
+            cargo.write_text('#!/bin/sh\n[ "$FAIL_METADATA" = 1 ] && exit 7\nprintf \'%s\\n\' "$TARGET_METADATA"\n')
+            cargo.chmod(0o755)
+            git = fake_bin / "git"
+            git.write_text("#!/bin/sh\nexit 128\n")
+            git.chmod(0o755)
+            (scripts / "qt-cargo.py").write_text(
+                'import os, pathlib, sys\n'
+                'target = pathlib.Path(os.environ["CARGO_TARGET_DIR"])\n'
+                'assert target == pathlib.Path(os.environ["EXPECTED_TARGET"]), target\n'
+                'if os.environ.get("FAIL_BUILD") == "1": sys.exit(9)\n'
+                '(target / "release").mkdir(parents=True, exist_ok=True)\n'
+                'binary = target / "release/qbz"\n'
+                'binary.write_text("#!/bin/sh\\nprintf \'artifact executed: %s\\\\n\' \\"$1\\"\\n")\n'
+                'binary.chmod(0o755)\n'
+            )
+            metadata = json.dumps({"target_directory": str(shared), "workspace_root": str(root / "crates")})
+            env = dict(os.environ, PATH=str(fake_bin) + os.pathsep + os.environ["PATH"],
+                       TARGET_METADATA=metadata, EXPECTED_TARGET=str(expected), NO_AUDIT="1",
+                       NO_TICKER="1", FORCE="1", NORUN="0", SMOKE="0", TEST="0", DEBUG="0",
+                       MOLD="0", XDG_CACHE_HOME=str(base / "cache"), FAIL_METADATA="1", FAIL_BUILD="0")
+            for name in targets.EXPLICIT_ENV:
+                env.pop(name, None)
+            command = ["bash", str(scripts / "qt-run.sh"), "fixture-argument"]
+            failed = subprocess.run(command, env=env, text=True, capture_output=True)
+            self.assertNotEqual(failed.returncode, 0)
+            self.assertFalse(expected.exists())
+            env.update(FAIL_METADATA="0", FAIL_BUILD="1")
+            failed = subprocess.run(command, env=env, text=True, capture_output=True)
+            self.assertEqual(failed.returncode, 9, failed.stderr)
+            self.assertFalse((root / "crates/target").is_symlink())
+            env["FAIL_BUILD"] = "0"
+            result = subprocess.run(command, env=env, text=True, capture_output=True)
+            self.assertEqual(result.returncode, 0, result.stderr)
+            self.assertIn("artifact executed: fixture-argument", result.stdout)
+            self.assertEqual((root / "crates/target/release/qbz").resolve(), expected / "release/qbz")
+            self.assertFalse((shared / "release/qbz").exists(), "the shared target is never built into")
 
 
 class SdkTests(unittest.TestCase):