diff --git a/crates/catalog/src/folders.rs b/crates/catalog/src/folders.rs
index 3861fd5f..61a8f8c4 100644
--- a/crates/catalog/src/folders.rs
+++ b/crates/catalog/src/folders.rs
@@ -5,10 +5,10 @@
 //! ones above them, never a folder that holds nothing of the library, with how many photos each
 //! holds — its subfolders included, like a year in By Date counts its months.
 //!
-//! Folders above the imported ones that hold nothing themselves and lead to a single folder fold
-//! into one row (`/Users/me/Pictures`) instead of a staircase of single-child levels; the row
-//! stands for the deepest folder it names. A folder spelled two ways (`/` or `\`, repeated or
-//! trailing separators, `.`) is one folder (see [`crate::query::folder_key`]).
+//! Every folder is a row of its own, the ones above the imported photos included
+//! (`/Users` → `me` → `Pictures`), so a row is exactly the folder it names. A folder spelled two
+//! ways (`/` or `\`, repeated or trailing separators, `.`) is one folder (see
+//! [`crate::query::folder_key`]).
 //!
 //! Each disk is a *volume*, a top-level row of its own: a drive letter (`D:`), a Windows share
 //! (`//server/share`), a mounted disk or share (macOS `/Volumes/tokyo`, Linux `/media/me/usb`,
@@ -41,8 +41,8 @@ pub const MAX_DEPTH: usize = 64;
 /// One row of the library's folder tree.
 #[derive(Clone, Debug, PartialEq, Serialize)]
 pub struct FolderNode {
-    /// What the row says: the folder's name, or the whole run (`Users/me/Pictures`) of folded
-    /// levels; for a volume, its name (`nas`, `D:`, `//server/share`, `/` for the startup disk).
+    /// What the row says: the folder's name; for a volume, its name (`nas`, `D:`,
+    /// `//server/share`, `/` for the startup disk).
     pub name: String,
     /// The folder the row stands for, written out from the names of the photos' paths (forward
     /// slashes, no verbatim prefix); hand it back to [`crate::Filter::library_folder`] to see its
@@ -205,17 +205,12 @@ impl Catalog {
     }
 }
 
-/// The node for `key` with everything below it (at most [`MAX_DEPTH`] deep), folding a level
-/// that holds nothing and leads to one folder into that folder (never a volume).
+/// The node for `key` with everything below it (at most [`MAX_DEPTH`] deep).
 fn build(key: &str, levels: &HashMap<String, Level>) -> Option<FolderNode> {
     let l = levels.get(key)?;
     let mut children: Vec<FolderNode> = l.children.iter().filter_map(|k| build(k, levels)).collect();
     sort(&mut children);
     let count = l.own + children.iter().map(|c| c.count).sum::<usize>();
-    if !l.volume && l.own == 0 && children.len() == 1 {
-        let c = children.remove(0);
-        return Some(FolderNode { name: format!("{}/{}", l.name, c.name), ..c });
-    }
     Some(FolderNode { name: l.name.clone(), path: l.path.clone(), count, own: l.own, volume: l.volume, selectable: true, children })
 }
 
diff --git a/crates/catalog/src/tests_folders.rs b/crates/catalog/src/tests_folders.rs
index 6c7c9ab7..1a5a6128 100644
--- a/crates/catalog/src/tests_folders.rs
+++ b/crates/catalog/src/tests_folders.rs
@@ -5,8 +5,7 @@
 //! * Given photos imported from several folders, the tree lists those folders and no others,
 //!   each with how many photos it holds, under the disk (volume) they are on.
 //! * A folder's count includes the folders inside it.
-//! * Folders above the imported ones that hold nothing themselves fold into one row, until the
-//!   library branches.
+//! * Every folder is a row of its own, the ones above the imported photos included.
 //! * Photos only browsed in Local, deleted photos and demo scenes are not "imported from" anywhere.
 //! * However a folder is spelled, it is one folder.
 //! * Choosing a folder shows what was imported from it and from the folders inside it — exactly
@@ -71,18 +70,27 @@ fn only_folders_with_imported_photos_are_listed_with_their_counts() {
 #[test]
 fn a_folders_count_includes_the_folders_inside_it() {
     let r = rows(&["/pics/trip/a.jpg", "/pics/trip/day1/b.jpg", "/pics/trip/day1/c.jpg", "/pics/trip/day2/d.jpg"]);
-    assert_eq!(r, vec![row("/", 4, 0), row("pics/trip", 4, 1), row("day1", 2, 2), row("day2", 1, 1)]);
+    assert_eq!(r, vec![row("/", 4, 0), row("pics", 4, 0), row("trip", 4, 1), row("day1", 2, 2), row("day2", 1, 1)]);
 }
 
 #[test]
-fn folders_that_hold_nothing_fold_into_one_row_until_the_library_branches() {
+fn every_folder_is_a_row_of_its_own_even_when_it_holds_nothing_itself() {
     let c = library(&["/Users/me/Pictures/2024/a.jpg", "/Users/me/Pictures/2025/b.jpg", "/Volumes/nas/photos/c.jpg"]);
     let tree = c.folder_tree();
     assert_eq!(
         outline(&tree),
-        vec![row("/", 2, 0), row("Users/me/Pictures", 2, 0), row("2024", 1, 1), row("2025", 1, 1), row("nas", 1, 0), row("photos", 1, 1)]
+        vec![
+            row("/", 2, 0),
+            row("Users", 2, 0),
+            row("me", 2, 0),
+            row("Pictures", 2, 0),
+            row("2024", 1, 1),
+            row("2025", 1, 1),
+            row("nas", 1, 0),
+            row("photos", 1, 1)
+        ]
     );
-    assert_eq!(tree[0].children[0].path, "/Users/me/Pictures", "the folded row stands for the deepest folder it names");
+    assert_eq!(tree[0].children[0].children[0].children[0].path, "/Users/me/Pictures", "a row is exactly the folder it names");
 }
 
 #[test]
@@ -99,13 +107,13 @@ fn browsed_deleted_and_demo_photos_are_not_imported_from_anywhere() {
     let id = c.alloc_photo_id();
     let demo = Photo::new(id, Source::Demo { scene: 1 }, "demo", "JPEG", 60, 40, "2026-01-01T10:00:00");
     c.apply(Op::AddPhoto { photo: Box::new(demo) }).unwrap();
-    assert_eq!(outline(&c.folder_tree()), vec![row("/", 1, 0), row("pics/kept", 1, 1)]);
+    assert_eq!(outline(&c.folder_tree()), vec![row("/", 1, 0), row("pics", 1, 0), row("kept", 1, 1)]);
 }
 
 #[test]
 fn however_a_folder_is_spelled_it_is_one_folder() {
     let r = rows(&["/pics/trip/a.jpg", "/pics//trip/./b.jpg", "/pics\\trip\\c.jpg", "/pics/x/../trip/d.jpg"]);
-    assert_eq!(r, vec![row("/", 4, 0), row("pics/trip", 4, 4)]);
+    assert_eq!(r, vec![row("/", 4, 0), row("pics", 4, 0), row("trip", 4, 4)]);
 }
 
 #[test]
@@ -159,7 +167,14 @@ fn shares_the_other_systems_mount_are_volumes_too() {
     let r = rows(&[r"\\tokyo.local\photos\a.jpg", r"\\192.168.1.5\scans\b.jpg", r"\\wsl$\Ubuntu\home\me\c.jpg", r"Z:\d.jpg"]);
     assert_eq!(
         r,
-        vec![row("//192.168.1.5/scans", 1, 1), row("//tokyo.local/photos", 1, 1), row("//wsl$/Ubuntu", 1, 0), row("home/me", 1, 1), row("Z:", 1, 1)]
+        vec![
+            row("//192.168.1.5/scans", 1, 1),
+            row("//tokyo.local/photos", 1, 1),
+            row("//wsl$/Ubuntu", 1, 0),
+            row("home", 1, 0),
+            row("me", 1, 1),
+            row("Z:", 1, 1)
+        ]
     );
 }
 
diff --git a/crates/engine/src/cmd/browse.rs b/crates/engine/src/cmd/browse.rs
index 338dff69..26d6130b 100644
--- a/crates/engine/src/cmd/browse.rs
+++ b/crates/engine/src/cmd/browse.rs
@@ -251,17 +251,9 @@ pub(crate) fn rename_folder_on_disk(from: &str, to: &str) -> std::result::Result
 
 /// After a folder moved from `from` to `to`: a browsed folder at or below it follows.
 pub(crate) fn follow_folder(s: &mut Session, from: &str, to: &str) {
-    // a chosen library folder at or below it follows too (compared the way the filter does, by
-    // folder identity, so a differently spelled choice is not widened to the folder itself)
-    if let Some(chosen) = s.filter.library_folder.clone() {
-        let (ck, fk) = (lightcraft_catalog::query::folder_key(&chosen), lightcraft_catalog::query::folder_key(from));
-        if !fk.is_empty()
-            && let Some(rest) = ck.strip_prefix(fk.as_str()).filter(|r| r.is_empty() || r.starts_with('/') || fk.ends_with('/'))
-        {
-            let rest = rest.trim_start_matches('/');
-            s.filter.library_folder = Some(if rest.is_empty() { to.to_string() } else { format!("{}/{rest}", to.trim_end_matches(['/', '\\'])) });
-        }
-    }
+    // a library folder chosen at or below it follows too, as a source or as a filter
+    follow_library_folder(&mut s.library_folder, from, to);
+    follow_library_folder(&mut s.filter.library_folder, from, to);
     if let Some(b) = &mut s.browse
         && let Ok(rel) = Path::new(&b.path).strip_prefix(from)
     {
@@ -271,6 +263,21 @@ pub(crate) fn follow_folder(s: &mut Session, from: &str, to: &str) {
     }
 }
 
+/// A chosen library folder at or below `from` becomes the same place below `to`. Compared the
+/// way the filter does, by folder identity, so a differently spelled choice is not widened to
+/// the folder itself.
+fn follow_library_folder(chosen: &mut Option<String>, from: &str, to: &str) {
+    let Some(c) = chosen.as_deref() else { return };
+    let (ck, fk) = (lightcraft_catalog::query::folder_key(c), lightcraft_catalog::query::folder_key(from));
+    if fk.is_empty() {
+        return;
+    }
+    if let Some(rest) = ck.strip_prefix(fk.as_str()).filter(|r| r.is_empty() || r.starts_with('/') || fk.ends_with('/')) {
+        let rest = rest.trim_start_matches('/');
+        *chosen = Some(if rest.is_empty() { to.to_string() } else { format!("{}/{rest}", to.trim_end_matches(['/', '\\'])) });
+    }
+}
+
 /// Rename or move a folder on disk (everything in it goes along, sidecars included) and relink
 /// the photos inside, as one undo step: undo renames the folder back and restores the photos'
 /// paths, redo repeats the move — each refused (and reported) when the destination is taken.
diff --git a/crates/engine/src/cmd/library.rs b/crates/engine/src/cmd/library.rs
index 688d84b3..844bae89 100644
--- a/crates/engine/src/cmd/library.rs
+++ b/crates/engine/src/cmd/library.rs
@@ -251,7 +251,7 @@ pub fn specs() -> Vec<CommandSpec> {
             "Show Source",
             [],
             None,
-            "{kind: all|recentlyAdded|album|recentlyDeleted|picks|missing, id?: albumId}",
+            "{kind: all|recentlyAdded|album|recentlyDeleted|picks|missing|libraryFolder, id?: albumId, path?: a path from library.folders (for libraryFolder)}",
             always,
             |s, p| {
                 let kind = str_param(p, "kind").unwrap_or("all");
@@ -268,6 +268,12 @@ pub fn specs() -> Vec<CommandSpec> {
                         }
                         LibrarySource::Album(a)
                     }
+                    "libraryFolder" => {
+                        let path = str_param(p, "path").map(str::trim).filter(|d| !lightcraft_catalog::query::folder_key(d).is_empty());
+                        let path = path.ok_or_else(|| bad("library.source", "libraryFolder needs the `path` of a folder from library.folders"))?;
+                        s.library_folder = Some(path.to_string());
+                        LibrarySource::LibraryFolder
+                    }
                     other => return Err(bad("library.source", format!("unknown source `{other}`"))),
                 };
                 let vis = s.visible_cloned();
@@ -334,6 +340,13 @@ pub fn specs() -> Vec<CommandSpec> {
                 if s.filter.library_folder.as_deref().is_some_and(|c| lightcraft_catalog::query::folder_within(c, path)) {
                     s.filter.library_folder = None;
                 }
+                // the folder being shown is gone: back to everything, as for a deleted album
+                if s.library_folder.as_deref().is_some_and(|c| lightcraft_catalog::query::folder_within(c, path)) {
+                    s.library_folder = None;
+                    if s.source == LibrarySource::LibraryFolder {
+                        s.source = LibrarySource::All;
+                    }
+                }
                 let vis = s.visible_cloned();
                 s.selection = vis.first().map(|f| Selection::single(*f)).unwrap_or_default();
                 Ok(json!({"removed": ids.len()}))
diff --git a/crates/engine/src/cmd/query.rs b/crates/engine/src/cmd/query.rs
index e7ffde14..9b0777b3 100644
--- a/crates/engine/src/cmd/query.rs
+++ b/crates/engine/src/cmd/query.rs
@@ -5,7 +5,7 @@ use lightcraft_develop::{CONTROLS, controls};
 use serde_json::{Value, json};
 
 use super::{CommandSpec, always, bad, cmd, has_active};
-use crate::Session;
+use crate::{LibrarySource, Session};
 
 pub fn photo_summary(p: &Photo) -> Value {
     json!({
@@ -81,10 +81,14 @@ pub fn specs() -> Vec<CommandSpec> {
             }))
         }),
         cmd!(query "library.state", "Library State", [], None, "{}", always, |s, _| {
-            let label = s.source.label(&s.catalog);
+            let label = match (s.source, s.library_folder.as_deref()) {
+                (LibrarySource::LibraryFolder, Some(path)) => lightcraft_catalog::folders::folder_label(path),
+                _ => s.source.label(&s.catalog),
+            };
             let n = s.visible().len();
             Ok(json!({
                 "source": s.source,
+                "libraryFolder": s.library_folder,
                 "sourceLabel": label,
                 "filter": s.filter,
                 "sort": s.sort,
diff --git a/crates/engine/src/lib.rs b/crates/engine/src/lib.rs
index cbbbbd63..bfc198dc 100644
--- a/crates/engine/src/lib.rs
+++ b/crates/engine/src/lib.rs
@@ -134,6 +134,9 @@ pub struct Session {
     pub clipboard: Option<Value>,
     /// The folder on disk the [`LibrarySource::Folder`] view browses.
     pub browse: Option<Browse>,
+    /// The folder the [`LibrarySource::LibraryFolder`] view shows: the library's photos imported
+    /// from it and from the folders inside it.
+    pub library_folder: Option<String>,
     /// Copied metadata (`photo.copyMetadata`): photo.setMeta params.
     pub meta_clipboard: Option<Value>,
     /// The photo that was active before the current one (Paste Settings from Previous).
@@ -234,6 +237,7 @@ impl Session {
             clipboard: None,
             meta_clipboard: None,
             browse: None,
+            library_folder: None,
             previous_active: None,
             copy_groups: lightcraft_develop::SettingsGroup::default_copy(),
             presets: presets::builtin(),
@@ -590,7 +594,8 @@ impl Session {
 
     /// Photos shown in the grid/filmstrip for the current source, filter and sort.
     pub fn visible(&mut self) -> &[PhotoId] {
-        let mut key = (self.catalog.revision, format!("{:?}|{:?}|{:?}|{:?}", self.source, self.filter, self.sort, self.browse));
+        let mut key =
+            (self.catalog.revision, format!("{:?}|{:?}|{:?}|{:?}|{:?}", self.source, self.filter, self.sort, self.browse, self.library_folder));
         if self.source == LibrarySource::Missing && self.media.availability.is_background() {
             // the view fills in as the background checks find files gone
             key.1.push_str(&format!("|{}", self.media.availability.generation()));
@@ -605,6 +610,10 @@ impl Session {
                 f.folder = Some(b.path);
                 f.subfolders = b.subfolders;
             }
+            if self.source == LibrarySource::LibraryFolder {
+                // no folder chosen: nothing (an empty path names no folder)
+                f.library_folder = Some(self.library_folder.clone().unwrap_or_default());
+            }
             let mut visible = self.catalog.query(&f, &self.sort);
             if matches!(self.source, LibrarySource::Album(_))
                 && self.sort.key == lightcraft_catalog::SortKey::CaptureDate
@@ -648,7 +657,7 @@ impl Session {
         if self.source == LibrarySource::Missing {
             return None;
         }
-        let key = (self.catalog.revision, format!("{:?}|{:?}", self.source, self.browse));
+        let key = (self.catalog.revision, format!("{:?}|{:?}|{:?}", self.source, self.browse, self.library_folder));
         if self.total.as_ref().map(|t| &t.0) != Some(&key) {
             let mut f = self.source.to_filter(&Filter::default(), &self.catalog);
             if self.source == LibrarySource::Folder {
@@ -656,6 +665,9 @@ impl Session {
                 f.folder = Some(b.path);
                 f.subfolders = b.subfolders;
             }
+            if self.source == LibrarySource::LibraryFolder {
+                f.library_folder = Some(self.library_folder.clone().unwrap_or_default());
+            }
             let n = self.catalog.query(&f, &self.sort).len();
             self.total = Some((key, n));
         }
diff --git a/crates/engine/src/library.rs b/crates/engine/src/library.rs
index 6a63e378..b6448380 100644
--- a/crates/engine/src/library.rs
+++ b/crates/engine/src/library.rs
@@ -102,6 +102,8 @@ struct PresetsFile {
 struct ViewFile {
     source: LibrarySource,
     browse: Option<crate::Browse>,
+    /// The folder a `libraryFolder` source shows.
+    library_folder: Option<String>,
     // No filter: a library opens unfiltered. A date, keyword or person left over from the last session
     // would silently hide photos, with only a small badge to say so.
     sort: lightcraft_catalog::Sort,
@@ -309,6 +311,7 @@ impl Session {
         self.pending_log.clear();
         self.selection = Selection::default();
         self.source = LibrarySource::All;
+        self.library_folder = None;
         if report.created && seed_demo {
             crate::demo::load(self);
             journal.snapshot(&self.catalog)?;
@@ -353,6 +356,11 @@ impl Session {
         if let Some(v) = settings.read::<ViewFile>(files.as_mut(), "view.json") {
             self.source = v.source;
             self.browse = v.browse;
+            self.library_folder = v.library_folder.filter(|f| !f.trim().is_empty());
+            if self.source == LibrarySource::LibraryFolder && self.library_folder.is_none() {
+                // no folder to show: everything, not an empty grid
+                self.source = LibrarySource::All;
+            }
             self.sort = v.sort;
             self.selection = v.selection;
             self.selection.ids.retain(|id| self.catalog.photo(*id).is_some());
@@ -500,7 +508,13 @@ impl Session {
     }
 
     fn view_json(&self) -> Vec<u8> {
-        let view = ViewFile { source: self.source, browse: self.browse.clone(), sort: self.sort, selection: self.selection.clone() };
+        let view = ViewFile {
+            source: self.source,
+            browse: self.browse.clone(),
+            library_folder: self.library_folder.clone(),
+            sort: self.sort,
+            selection: self.selection.clone(),
+        };
         serde_json::to_vec_pretty(&view).unwrap_or_default()
     }
 
diff --git a/crates/engine/src/tests_folders.rs b/crates/engine/src/tests_folders.rs
index 887870b5..e9577443 100644
--- a/crates/engine/src/tests_folders.rs
+++ b/crates/engine/src/tests_folders.rs
@@ -14,6 +14,10 @@ use serde_json::json;
 
 use crate::{LibrarySource, Session, filter_chips};
 
+fn source_folder(s: &mut Session, path: &str) -> serde_json::Value {
+    s.execute("library.source", &json!({"kind": "libraryFolder", "path": path})).unwrap()
+}
+
 fn add(s: &mut Session, path: &str) {
     let id = s.catalog.alloc_photo_id();
     let p = Photo::new(id, Source::File { path: path.into() }, "x.jpg", "JPEG", 60, 40, "2026-01-01T10:00:00");
@@ -230,3 +234,78 @@ fn following_a_folder_reads_both_spellings_the_same_way() {
     crate::cmd::browse::follow_folder(&mut s, "/a/b", "/a/c");
     assert_eq!(s.filter.library_folder.as_deref(), Some("/elsewhere/b"), "other folders are left alone");
 }
+
+#[test]
+fn choosing_a_folder_replaces_the_source_the_way_an_album_does() {
+    let mut s = session();
+    s.execute("library.source", &json!({"kind": "picks"})).unwrap();
+    assert_eq!(s.visible().len(), 0, "no picks");
+    let r = source_folder(&mut s, "/pics/trip");
+    assert_eq!(r["count"], 2, "the folder's photos, whatever was shown before");
+    assert_eq!((s.source, s.library_folder.as_deref()), (LibrarySource::LibraryFolder, Some("/pics/trip")));
+    assert!(filter_chips(&s.filter, &s.catalog).is_empty(), "a source is not a filter chip");
+    let state = s.execute("library.state", &json!({})).unwrap();
+    assert_eq!((state["sourceLabel"].as_str(), state["libraryFolder"].as_str()), (Some("pics/trip"), Some("/pics/trip")), "agents see which folder");
+    // the filter bar narrows it further, as it does an album
+    s.execute("library.filter", &json!({"rating": 1})).unwrap();
+    assert_eq!(s.visible().len(), 0);
+    s.execute("library.clearFilter", &json!({})).unwrap();
+    assert_eq!(s.visible().len(), 2);
+    s.execute("library.source", &json!({"kind": "all"})).unwrap();
+    assert_eq!(s.visible().len(), 3, "back to everything");
+}
+
+#[test]
+fn the_folder_source_takes_a_library_folder_path_only() {
+    let mut s = session();
+    for params in [
+        json!({"kind": "libraryFolder"}),
+        json!({"kind": "libraryFolder", "path": 5}),
+        json!({"kind": "libraryFolder", "path": "  "}),
+        json!({"kind": "libraryFolder", "path": "."}),
+    ] {
+        assert!(s.execute("library.source", &params).is_err(), "{params}");
+    }
+    assert_eq!(s.source, LibrarySource::All, "refused, nothing changed");
+    assert_eq!(source_folder(&mut s, "/elsewhere")["count"], 0, "a folder with no photos shows nothing, not everything");
+}
+
+#[test]
+fn removing_the_folder_being_shown_returns_to_all_photos() {
+    let mut s = session();
+    source_folder(&mut s, "/pics/trip");
+    s.execute("library.removeFolder", &json!({"path": "/pics/trip"})).unwrap();
+    assert_eq!((s.source, s.library_folder.as_deref()), (LibrarySource::All, None));
+    assert_eq!(s.visible().len(), 1);
+    // removing another folder leaves the source alone
+    let mut s = session();
+    source_folder(&mut s, "/pics/home");
+    s.execute("library.removeFolder", &json!({"path": "/pics/trip"})).unwrap();
+    assert_eq!(s.source, LibrarySource::LibraryFolder);
+    assert_eq!(s.visible().len(), 1);
+}
+
+#[test]
+fn a_renamed_folder_stays_the_one_shown_and_undo_follows_it_back() {
+    let dir = Scratch::new("source-rename");
+    std::fs::create_dir_all(dir.0.join("trip/day1")).unwrap();
+    let (trip, day1, renamed) = (dir.path("trip"), dir.path("trip/day1"), dir.path("holiday"));
+    let mut s = Session::new();
+    add(&mut s, &format!("{trip}/a.jpg"));
+    add(&mut s, &format!("{day1}/b.jpg"));
+    source_folder(&mut s, &day1);
+    s.execute("folder.rename", &json!({"path": trip, "name": "holiday"})).unwrap();
+    assert_eq!(s.library_folder.as_deref(), Some(format!("{renamed}/day1").as_str()), "the subfolder follows its parent");
+    assert_eq!(s.visible().len(), 1);
+    s.execute("edit.undo", &json!({})).unwrap();
+    assert_eq!(s.library_folder.as_deref(), Some(day1.as_str()));
+    assert_eq!(s.visible().len(), 1);
+}
+
+#[test]
+fn the_shown_folder_follows_reading_both_spellings_the_same_way() {
+    let mut s = Session::new();
+    s.library_folder = Some("/a/x/../b/sub".into());
+    crate::cmd::browse::follow_folder(&mut s, "/a/b", "/a/c");
+    assert_eq!(s.library_folder.as_deref(), Some("/a/c/sub"));
+}
diff --git a/crates/engine/src/tests_library.rs b/crates/engine/src/tests_library.rs
index 45a56b2e..91ae195a 100644
--- a/crates/engine/src/tests_library.rs
+++ b/crates/engine/src/tests_library.rs
@@ -212,6 +212,23 @@ fn profile_favorites_and_recent_survive_reopen() {
     let _ = std::fs::remove_dir_all(&dir);
 }
 
+#[test]
+fn the_shown_library_folder_survives_reopen() {
+    let dir = temp_dir("libfolder");
+    let mut s = open(&dir, true);
+    s.execute("library.source", &json!({"kind": "libraryFolder", "path": "/pics/trip"})).unwrap();
+    s.save_view();
+    drop(s);
+    let s = open(&dir, false);
+    assert_eq!((s.source, s.library_folder.as_deref()), (crate::LibrarySource::LibraryFolder, Some("/pics/trip")));
+    drop(s);
+    // a view file that names the source but no folder opens on everything, never an empty grid
+    std::fs::write(dir.join("view.json"), br#"{"source": {"kind": "libraryFolder"}}"#).unwrap();
+    let s = open(&dir, false);
+    assert_eq!((s.source, s.library_folder), (crate::LibrarySource::All, None));
+    let _ = std::fs::remove_dir_all(&dir);
+}
+
 /// Smart albums with a rule set: all / any / none, nested groups, validation, live updates.
 #[test]
 fn smart_album_rule_sets() {
diff --git a/crates/engine/src/view.rs b/crates/engine/src/view.rs
index 1b0f0ca4..18149929 100644
--- a/crates/engine/src/view.rs
+++ b/crates/engine/src/view.rs
@@ -19,6 +19,9 @@ pub enum LibrarySource {
     Folder,
     /// Photos whose original file can't be found (`library.missing`).
     Missing,
+    /// A folder the library's photos were imported from ([`crate::Session::library_folder`]),
+    /// and the folders inside it (`library.folders`).
+    LibraryFolder,
 }
 
 /// The folder a [`LibrarySource::Folder`] view shows.
@@ -49,7 +52,7 @@ impl LibrarySource {
             LibrarySource::RecentlyDeleted => f.deleted = true,
             LibrarySource::Picks => f.flag = Some(lightcraft_catalog::Flag::Pick),
             // the folder itself is filled in by the session (it holds the path)
-            LibrarySource::Folder | LibrarySource::Missing => {}
+            LibrarySource::Folder | LibrarySource::Missing | LibrarySource::LibraryFolder => {}
         }
         f
     }
@@ -62,6 +65,7 @@ impl LibrarySource {
             LibrarySource::RecentlyDeleted => "Recently Deleted".into(),
             LibrarySource::Picks => "Picks".into(),
             LibrarySource::Folder => "Folder".into(),
+            LibrarySource::LibraryFolder => "Folder".into(),
             LibrarySource::Missing => "Missing Photos".into(),
         }
     }
diff --git a/crates/ui-egui/src/i18n.rs b/crates/ui-egui/src/i18n.rs
index 98763184..7ed26d56 100644
--- a/crates/ui-egui/src/i18n.rs
+++ b/crates/ui-egui/src/i18n.rs
@@ -216,6 +216,15 @@ pub fn source_label(source: lightcraft_engine::LibrarySource, catalog: &lightcra
     if matches!(source, lightcraft_engine::LibrarySource::Album(id) if catalog.album(id).is_some()) { label } else { tr(&label).to_string() }
 }
 
+/// What the grid is titled for the session's source: [`source_label`], or a library folder's last
+/// two names (`photos/travel`; the folder's name is the user's and stays verbatim).
+pub fn source_title(session: &lightcraft_engine::Session) -> String {
+    match (session.source, session.library_folder.as_deref()) {
+        (lightcraft_engine::LibrarySource::LibraryFolder, Some(path)) => lightcraft_catalog::folders::folder_label(path),
+        (source, _) => source_label(source, &session.catalog),
+    }
+}
+
 /// A date group heading (`2026-09-20`, `2026-09`, `2026`) in the UI language: the grid's full
 /// form, or the date sidebar's `short` one ("Sunday, 20" / "September" / "2026"). English keeps the
 /// catalog's own wording; every other language formats it with its `*-formats.json` date
diff --git a/crates/ui-egui/src/panels/grid.rs b/crates/ui-egui/src/panels/grid.rs
index 7dc07602..bb7b27f0 100644
--- a/crates/ui-egui/src/panels/grid.rs
+++ b/crates/ui-egui/src/panels/grid.rs
@@ -150,7 +150,7 @@ fn show_inner(app: &mut LightcraftApp, ui: &mut egui::Ui) {
             folder_header(app, ui, hr, &b, &ids, local, &cnt)
         }
         None => {
-            let title = crate::i18n::source_label(app.session.source, &app.session.catalog);
+            let title = crate::i18n::source_title(&app.session);
             ui.painter().text(pos2(hr.left() + 20.0, hr.center().y), Align2::LEFT_CENTER, &title, t.semibold(17.0), t.text);
             ui.painter().text(pos2(hr.right() - 20.0, hr.center().y), Align2::RIGHT_CENTER, cnt, t.font(12.5), t.text_dim);
         }
@@ -164,11 +164,7 @@ fn show_inner(app: &mut LightcraftApp, ui: &mut egui::Ui) {
         if !chips.is_empty() {
             let body = match total {
                 Some(n) if n > 0 => {
-                    crate::i18n::tr_format!(
-                        "{n} photos in {} are hidden by the filters above",
-                        crate::i18n::source_label(app.session.source, &app.session.catalog),
-                        n = n
-                    )
+                    crate::i18n::tr_format!("{n} photos in {} are hidden by the filters above", crate::i18n::source_title(&app.session), n = n)
                 }
                 _ => "Remove a filter above, or choose Clear all".to_string(),
             };
diff --git a/crates/ui-egui/src/panels/left.rs b/crates/ui-egui/src/panels/left.rs
index 884d346a..be47fa21 100644
--- a/crates/ui-egui/src/panels/left.rs
+++ b/crates/ui-egui/src/panels/left.rs
@@ -733,8 +733,9 @@ fn is_within(app: &LightcraftApp, id: lightcraft_catalog::AlbumId, ancestor: lig
 }
 
 /// "Folders": where on disk the library's photos were imported from, with photo counts (see
-/// `lightcraft_catalog::folders`). A click shows the photos imported from that folder and the
-/// folders inside it, the triangle opens a level. Only folders holding imported photos are
+/// `lightcraft_catalog::folders`). A click makes that folder the source, like an album or a
+/// Local folder: its photos and those of the folders inside it fill the grid. The triangle opens
+/// a level. Only folders holding imported photos are
 /// listed; every folder on disk is under Local.
 fn folders_section(app: &mut LightcraftApp, ui: &mut egui::Ui) {
     let tree = app.caches.folder_tree(&app.session.catalog);
@@ -774,10 +775,11 @@ fn elide_head(text: &str, max: f32, width: impl Fn(&str) -> f32) -> String {
     "…".to_string()
 }
 
-/// Whenever the chosen folder changes (a click, an agent, a rename or its undo), open the rows
+/// Whenever the shown folder changes (a click, an agent, a rename or its undo), open the rows
 /// above it so it is on screen; folding one by hand afterwards sticks until the choice changes.
 fn reveal_chosen(app: &LightcraftApp, ui: &egui::Ui, tree: &[FolderNode]) {
-    let chosen = app.session.filter.library_folder.clone().filter(|c| !lightcraft_catalog::query::folder_key(c).is_empty());
+    let shown = app.session.library_folder.clone().filter(|_| app.session.source == LibrarySource::LibraryFolder);
+    let chosen = shown.filter(|c| !lightcraft_catalog::query::folder_key(c).is_empty());
     let seen = egui::Id::new("libfolder-revealed");
     let now = chosen.as_deref().map(lightcraft_catalog::query::folder_key);
     if ui.data(|d| d.get_temp::<Option<String>>(seen)) == Some(now.clone()) {
@@ -802,11 +804,15 @@ fn folder_rows(app: &mut LightcraftApp, ui: &mut egui::Ui, nodes: &[FolderNode],
     for n in nodes {
         let key = lightcraft_catalog::query::folder_key(&n.path);
         let open_id = egui::Id::new(("libfolder-open", key.clone()));
-        // a disk starts open: its folders are what the section is for
-        let mut open: bool = ui.data(|d| d.get_temp(open_id)).unwrap_or(n.volume);
+        // a disk starts open, and so does a folder that holds nothing itself and leads to one
+        // folder (`Users` → `me`): the first row where the library branches is what you look for
+        let leads_on = n.own == 0 && n.children.len() == 1;
+        let mut open: bool = ui.data(|d| d.get_temp(open_id)).unwrap_or(n.volume || leads_on);
         // a row whose path would cover other disks' photos too only opens and closes
         let selectable = n.selectable;
-        let sel = selectable && app.session.filter.library_folder.as_deref().is_some_and(|f| same_folder(f, &n.path));
+        let sel = selectable
+            && app.session.source == LibrarySource::LibraryFolder
+            && app.session.library_folder.as_deref().is_some_and(|f| same_folder(f, &n.path));
         let name = if selectable { n.name.clone() } else { crate::i18n::tr("This Computer").to_string() };
         // room for the name: between the icon and the count
         let font = t.font(13.5);
@@ -837,12 +843,8 @@ fn folder_rows(app: &mut LightcraftApp, ui: &mut egui::Ui, nodes: &[FolderNode],
         let resp = resp.on_hover_text(tip);
         if resp.clicked() && !toggled {
             if selectable {
-                // the library's folder, not a mix with the Local folder being browsed
-                if app.session.source == LibrarySource::Folder {
-                    let _ = app.run("library.source", json!({"kind": "all"}));
-                }
-                let v = if sel { serde_json::Value::Null } else { json!(n.path) };
-                let _ = app.run("library.filter", json!({"libraryFolder": v}));
+                // a source like an album or a Local folder: it replaces what the grid showed
+                let _ = app.run("library.source", json!({"kind": "libraryFolder", "path": n.path}));
             } else {
                 toggled = true;
             }
diff --git a/crates/ui-egui/src/tests_panels.rs b/crates/ui-egui/src/tests_panels.rs
index e5134290..585a3e95 100644
--- a/crates/ui-egui/src/tests_panels.rs
+++ b/crates/ui-egui/src/tests_panels.rs
@@ -241,9 +241,11 @@ fn folders_section_lists_where_photos_were_imported_from_and_narrows_the_grid()
     assert_eq!(h.app.session.visible().len(), 3);
     click(&mut h, "source:libfolder:/pics/trip");
     assert_eq!(h.app.session.visible().len(), 2, "only the photos imported from that folder");
-    assert_eq!(h.app.session.filter.library_folder.as_deref(), Some("/pics/trip"));
-    click(&mut h, "source:libfolder:/pics/trip");
-    assert_eq!(h.app.session.visible().len(), 3, "choosing it again shows everything");
+    assert_eq!(h.app.session.source, lightcraft_engine::LibrarySource::LibraryFolder);
+    assert_eq!(h.app.session.library_folder.as_deref(), Some("/pics/trip"));
+    assert_eq!(h.app.session.filter, lightcraft_catalog::Filter::default(), "a source, not a filter");
+    click(&mut h, "source:all");
+    assert_eq!(h.app.session.visible().len(), 3, "All Photos shows everything again");
     // the section folds like the others
     click(&mut h, "sidebarSection:folders");
     assert!(!has(&h, "source:libfolder:/pics"), "folded");
@@ -259,7 +261,7 @@ fn disks_are_rows_of_their_own() {
     assert!(has(&h, "source:libfolder:/") && has(&h, "source:libfolder:/Volumes/nas"), "both disks are listed");
     assert!(has(&h, "source:libfolder:/Volumes/nas/p"), "an open disk shows its folders");
     click(&mut h, "source:libfolder:/");
-    assert_eq!(h.app.session.filter.library_folder, None, "the startup disk's path would cover every disk");
+    assert_eq!(h.app.session.library_folder, None, "the startup disk's path would cover every disk");
     assert!(!has(&h, "source:libfolder:/Users/me"), "a click on it folds it instead");
     click(&mut h, "source:libfolder:/");
     assert!(has(&h, "source:libfolder:/Users/me"));
@@ -267,15 +269,42 @@ fn disks_are_rows_of_their_own() {
     assert_eq!(h.app.session.visible().len(), 2, "everything on the nas");
 }
 
-/// Choosing a folder while Local is the source shows the library's folder, not a mix.
+/// A folder loads into the grid the way an album, a Local folder or Picks does: whatever was
+/// shown before is replaced, and the folder's own row is highlighted.
 #[test]
-fn choosing_a_library_folder_leaves_a_local_folder_view() {
+fn choosing_a_library_folder_replaces_whatever_was_shown() {
+    use lightcraft_engine::LibrarySource;
     let mut h = folders_app(&["/pics/trip/a.jpg", "/pics/home/b.jpg"]);
-    h.app.session.source = lightcraft_engine::LibrarySource::Folder;
     click(&mut h, "libraryFolderToggle:/pics");
+    for before in [LibrarySource::Picks, LibrarySource::Folder, LibrarySource::RecentlyDeleted, LibrarySource::Missing] {
+        h.app.session.source = before;
+        click(&mut h, "source:libfolder:/pics/trip");
+        assert_eq!(h.app.session.source, LibrarySource::LibraryFolder, "from {before:?}");
+        assert_eq!(h.app.session.visible().len(), 1);
+    }
     click(&mut h, "source:libfolder:/pics/trip");
-    assert_eq!(h.app.session.source, lightcraft_engine::LibrarySource::All);
-    assert_eq!(h.app.session.visible().len(), 1);
+    assert_eq!(h.app.session.source, LibrarySource::LibraryFolder, "choosing it again keeps it, as an album does");
+    click(&mut h, "source:libfolder:/pics/home");
+    assert_eq!(h.app.session.library_folder.as_deref(), Some("/pics/home"));
+}
+
+#[test]
+fn the_grid_is_titled_after_the_folder() {
+    let mut h = folders_app(&["/Volumes/tokyo/photos/travel/a.jpg"]);
+    h.app.session.source = lightcraft_engine::LibrarySource::LibraryFolder;
+    h.app.session.library_folder = Some("/Volumes/tokyo/photos/travel".into());
+    assert_eq!(crate::i18n::source_title(&h.app.session), "photos/travel");
+    h.app.session.source = lightcraft_engine::LibrarySource::All;
+    assert_eq!(crate::i18n::source_title(&h.app.session), "All Photos");
+}
+
+/// A folder that holds nothing itself and leads to one folder starts open: the tree opens down to
+/// where the library branches.
+#[test]
+fn a_chain_of_single_folders_starts_open() {
+    let h = folders_app(&["/Users/me/Pictures/2024/a.jpg", "/Users/me/Pictures/2025/b.jpg"]);
+    assert!(has(&h, "source:libfolder:/Users/me/Pictures"), "Users and me opened by themselves");
+    assert!(!has(&h, "source:libfolder:/Users/me/Pictures/2024"), "the branching folder waits to be opened");
 }
 
 /// Removing a folder from the library asks first, then moves its photos to Recently Deleted.
@@ -310,7 +339,7 @@ fn a_folder_that_holds_other_disks_only_opens() {
     let mut h = folders_app(&["/Volumes/1.jpg", "/Volumes/tokyo/x.jpg"]);
     assert!(has(&h, "source:libfolder:/Volumes"));
     click(&mut h, "source:libfolder:/Volumes");
-    assert_eq!(h.app.session.filter.library_folder, None, "choosing it would show the tokyo disk too");
+    assert_eq!(h.app.session.library_folder, None, "choosing it would show the tokyo disk too");
     click(&mut h, "source:libfolder:/Volumes/tokyo");
     assert_eq!(h.app.session.visible().len(), 1, "a disk's own row does choose");
 }
@@ -320,7 +349,8 @@ fn a_folder_that_holds_other_disks_only_opens() {
 fn the_chosen_folder_is_always_in_view() {
     let mut h = folders_app(&["/pics/trip/day1/a.jpg", "/pics/trip/b.jpg", "/pics/home/c.jpg"]);
     assert!(!has(&h, "source:libfolder:/pics/trip/day1"), "folded to begin with");
-    h.app.session.filter.library_folder = Some("/pics/trip/day1".into());
+    h.app.session.source = lightcraft_engine::LibrarySource::LibraryFolder;
+    h.app.session.library_folder = Some("/pics/trip/day1".into());
     h.step();
     h.step();
     assert!(has(&h, "source:libfolder:/pics/trip/day1"), "the rows above it opened");
@@ -337,7 +367,8 @@ fn a_renamed_folder_keeps_its_place_in_the_tree() {
     std::fs::create_dir_all(base.join("pics/home")).unwrap();
     let b = base.to_string_lossy().to_string();
     let mut h = folders_app(&[&format!("{b}/pics/trip/a.jpg"), &format!("{b}/pics/home/b.jpg")]);
-    h.app.session.filter.library_folder = Some(format!("{b}/pics/trip"));
+    h.app.session.source = lightcraft_engine::LibrarySource::LibraryFolder;
+    h.app.session.library_folder = Some(format!("{b}/pics/trip"));
     h.step();
     h.step();
     assert!(has(&h, &format!("source:libfolder:{b}/pics/trip")));
diff --git a/docs/parity.md b/docs/parity.md
index 23582ca3..206e2c3e 100644
--- a/docs/parity.md
+++ b/docs/parity.md
@@ -718,7 +718,7 @@ From `08-lightroom-classic-extras.md` (Classic-only features) and part 2 of `06-
 | LRC-LIB-CATALOG-PANEL | Catalog sets | P1 | ✅ | `cmd:library.source` (`missing`) | all, recently added, picks, recently deleted, missing photos (when any) |
 | LRC-LIB-CATALOG-LOCK | Catalog open in one program at a time | P1 | ✅ | `cmd:app.openLibrary`, `crates/catalog/src/lock.rs`, `crates/engine/src/library.rs` (`open_library`) | exclusive OS lock on `catalog.lock` for the session (app and `lightcraft-cli --library`); a second opener is refused with who has it (`catalog.lock.owner`: program, process, computer); released by the OS on a crash, so never stale; file systems without locks open unprotected with a warning; no read-only mode; the browser build (OPFS) has no guard across tabs yet. A library that can't be opened at launch (locked, unreadable, newer format, drive missing) shows a window — Try Again, Choose Another Library…, Continue Without Saving (then a banner; nothing written), Quit — instead of a silent demo session (`crates/ui-egui/src/panels/library_problem.rs`) |
 | LRC-LIB-FOLDERS | Disk folder tree | P1 | ✅ | `cmd:library.browse`, `cmd:folder.rename`, `cmd:folder.move`, `crates/ui-egui/src/panels/left.rs` (`local_section`, `folder_tree`) | standard places + the browsed folder + Browse Folder…, each an expandable tree of subfolders, breadcrumb navigation; context menu: Rename Folder…, Move Folder To…, Show in Finder (on disk, photos relinked; one undo step each: undo / redo move the folder back and forth, refused when the destination is taken) |
-| LRC-LIB-LIBFOLDERS | Library folders | P1 | ✅ | `cmd:library.folders`, `cmd:library.filter` (`libraryFolder`), `cmd:library.removeFolder`, `cmd:folder.rename`, `cmd:folder.move`, `crates/catalog/src/folders.rs`, `crates/ui-egui/src/panels/left.rs` (`folders_section`, `folder_menu_for_library`, `row_menu`), `crates/ui-egui/src/tests_panels.rs` | sidebar Folders: the folders the library's photos were imported from, with photo counts (subfolders included), as another way to explore the library next to By Date and Keywords; Local stays the way to browse any folder on disk. Each disk is a row of its own and starts open: a drive letter, a Windows share (`\\server\share`, `\\?\UNC\…`, `\\wsl$\…`), a macOS share or disk (`/Volumes/tokyo`), a Linux mount (`/media`, `/run/media`, `/mnt`, gvfs `smb-share:…`, `/net/<host>`), NFS (`/Network/Servers/<host>`), else “This Computer” — told apart from the stored paths alone, so an offline share lists like a mounted one and the sidebar never waits on a network. Only folders that hold imported photos are listed (browsed, deleted and demo photos don't count); levels that hold nothing and lead to one folder fold into one row (`Users/me/Pictures`); long names are cut at the end with the full path in the tooltip; click chooses a folder and the folders inside it (click again clears; chip “Folder: pics/trip”), and its row is always opened into view, also after a rename or move and their undo. A row that would cover other disks' photos too (the startup disk, `/Volumes`, `/mnt`…) only opens. Right-click (row or triangle): Rename Folder…, Move Folder To…, Show in Finder (on disk, photos relinked, as in Local) and Remove from Library… (asks; moves the folder's photos to Recently Deleted, one undo step, no file touched); a disk row offers Remove Disk from Library… (the command needs `disk: true` for a whole disk or a folder spanning several). Limits: names are compared as written (macOS `/Volumes/tokyo` vs `/Volumes/TOKYO` are two disks; `/Volumes/Macintosh HD/…` and `/…` two rows); no disk capacity / online status; no “include subfolders” switch (a folder always includes the ones inside it); creating a folder and moving photos between folders are not here |
+| LRC-LIB-LIBFOLDERS | Library folders | P1 | ✅ | `cmd:library.folders`, `cmd:library.source` (`libraryFolder`), `cmd:library.filter` (`libraryFolder`), `cmd:library.removeFolder`, `cmd:folder.rename`, `cmd:folder.move`, `crates/catalog/src/folders.rs`, `crates/ui-egui/src/panels/left.rs` (`folders_section`, `folder_menu_for_library`, `row_menu`), `crates/ui-egui/src/tests_panels.rs` | sidebar Folders: the folders the library's photos were imported from, with photo counts (subfolders included), as another way to explore the library next to By Date and Keywords; Local stays the way to browse any folder on disk. Each disk is a row of its own and starts open: a drive letter, a Windows share (`\\server\share`, `\\?\UNC\…`, `\\wsl$\…`), a macOS share or disk (`/Volumes/tokyo`), a Linux mount (`/media`, `/run/media`, `/mnt`, gvfs `smb-share:…`, `/net/<host>`), NFS (`/Network/Servers/<host>`), else “This Computer” — told apart from the stored paths alone, so an offline share lists like a mounted one and the sidebar never waits on a network. Only folders that hold imported photos are listed (browsed, deleted and demo photos don't count); every folder is a row of its own (`Users` → `me` → `Pictures`), and a folder that holds nothing itself and leads to one folder starts open; long names are cut at the end with the full path in the tooltip; click makes the folder the source, like an album or a Local folder (its photos and those of the folders inside it fill the grid, titled “photos/travel”; the filter bar narrows it further; `library.source` `libraryFolder` + `path`; kept with the library's view), and its row is always opened into view, also after a rename or move and their undo. A row that would cover other disks' photos too (the startup disk, `/Volumes`, `/mnt`…) only opens. Right-click (row or triangle): Rename Folder…, Move Folder To…, Show in Finder (on disk, photos relinked, as in Local) and Remove from Library… (asks; moves the folder's photos to Recently Deleted, one undo step, no file touched); a disk row offers Remove Disk from Library… (the command needs `disk: true` for a whole disk or a folder spanning several). Limits: names are compared as written (macOS `/Volumes/tokyo` vs `/Volumes/TOKYO` are two disks; `/Volumes/Macintosh HD/…` and `/…` two rows); no disk capacity / online status; no “include subfolders” switch (a folder always includes the ones inside it); creating a folder and moving photos between folders are not here |
 | LRC-LIB-COLLECTIONS | Collections & sets | P1 | ✅ | `cmd:album.create`, `cmd:album.createSmart`, `cmd:album.toggleTarget`, `cmd:album.setTarget`, `cmd:album.clearQuick` | albums + folders (sets), smart albums (rule editor; rules incl. File Path — the whole string, either separator, case-insensitive), Quick Collection and target album (B in the grids adds / removes the selection; album menu ▸ Set as Target Album; the target is marked +) |
 | LRC-LIB-SMARTCOLL | Smart-collection rules | P1 | ✅ | `cmd:album.createSmart`, `cmd:album.setRules`, `cmd:album.ruleFields`, `cmd:dialog.smartAlbum`, `crates/catalog/src/rules.rs`, `crates/ui-egui/src/panels/rules_editor.rs` | rule editor: match all / any / none, nested groups (⌥+ or + Group), 30 fields (rating, flag, label, type, edits, keywords, any text, filename, file path, format, title, caption, camera, lens, location, creator, copyright, copyright status, capture / import / edit date, ISO, aperture, focal length, megapixels, GPS, virtual copy, album) with text / number / date / in-the-last operators; live match count; also usable as a library filter (`ruleSet`) |
 | LRC-LIB-PUBLISH | Publish services | P2 | ⬜ | | |