diff --git a/src/app/actions.rs b/src/app/actions.rs
index 56d773d..5b2b97b 100644
--- a/src/app/actions.rs
+++ b/src/app/actions.rs
@@ -30,6 +30,10 @@ gpui_kit::actions!(
         FocusSearch,
         /// Connect the session selected in the focused session list.
         ConnectSelected,
+        /// Expand every group in the session tree.
+        ExpandAllGroups,
+        /// Collapse every group in the session tree.
+        CollapseAllGroups,
         /// Close the center tab displayed most recently (the one ⌘W acts on).
         CloseActiveTab,
         /// Increase the application base font (interface zoom).
@@ -108,6 +112,10 @@ session_action!(
     DeleteSession
 );
 
+group_action!(
+    /// Open a terminal connection for every session in this group's subtree.
+    ConnectGroup
+);
 group_action!(
     /// Open the new-session dialog with this group pre-selected.
     NewSessionInGroup
diff --git a/src/session/database.rs b/src/session/database.rs
index 55bb005..3202bb9 100644
--- a/src/session/database.rs
+++ b/src/session/database.rs
@@ -218,6 +218,13 @@ impl SessionDatabase {
         Ok(())
     }
 
+    /// Save an expand-all or collapse-all command in one database write.
+    pub fn set_all_groups_expanded(&self, expanded: bool) -> rusqlite::Result<()> {
+        self.connection
+            .execute("UPDATE groups SET expanded = ?1", params![expanded])?;
+        Ok(())
+    }
+
     /// Deleting a group takes its subgroups and their sessions with it, via
     /// the `ON DELETE CASCADE` on both foreign keys.
     pub fn remove_group(&self, id: GroupId) -> rusqlite::Result<()> {
diff --git a/src/session/session_dialog.rs b/src/session/session_dialog.rs
index 0663140..d1b3525 100644
--- a/src/session/session_dialog.rs
+++ b/src/session/session_dialog.rs
@@ -1,9 +1,9 @@
-use std::rc::Rc;
+use std::{rc::Rc, time::Duration};
 
 use gpui_kit::component::{
     ActiveTheme as _, IndexPath, Sizable as _, WindowExt as _,
     button::{Button, ButtonVariant, ButtonVariants as _},
-    dialog::{DialogAction, DialogButtonProps, DialogClose, DialogFooter},
+    dialog::{Cancel, Confirm, DialogButtonProps, DialogFooter},
     form::{Field, Form},
     h_flex,
     input::{Input, InputContentType, InputEvent, InputState},
@@ -12,6 +12,7 @@ use gpui_kit::component::{
 };
 use gpui_kit::prelude::FluentBuilder as _;
 use gpui_kit::*;
+use tokio::io::{AsyncReadExt as _, AsyncWriteExt as _};
 use zeroize::Zeroizing;
 
 use crate::secrets::{SecretRef, SharedSecretStore};
@@ -51,6 +52,8 @@ pub struct SessionForm {
     /// Parallel to the group select's rows; `None` is the root of the tree.
     group_ids: Vec<Option<GroupId>>,
     error: Option<SharedString>,
+    testing_connection: bool,
+    connection_test_result: Option<(bool, SharedString)>,
     editing_connected: bool,
     /// Where saved secrets are read from. Writes go through the store, which
     /// owns the one error channel.
@@ -179,6 +182,8 @@ impl SessionForm {
             group,
             group_ids,
             error: None,
+            testing_connection: false,
+            connection_test_result: None,
             editing_connected,
             secrets,
             password_loaded: false,
@@ -278,6 +283,51 @@ impl SessionForm {
         .detach();
     }
 
+    /// Probe the endpoint currently shown in the form without saving it.
+    fn test_connection(&mut self, _: &ClickEvent, _: &mut Window, cx: &mut Context<Self>) {
+        if self.testing_connection {
+            return;
+        }
+        let host = self.host.read(cx).value().trim().to_string();
+        let port = self.port.read(cx).value().trim().parse::<u16>();
+        let error = if host.is_empty() {
+            Some("请输入主机")
+        } else if !matches!(port, Ok(1..=u16::MAX)) {
+            Some("端口必须是 1 到 65535 之间的数字")
+        } else {
+            None
+        };
+        if let Some(error) = error {
+            self.connection_test_result = Some((false, error.into()));
+            cx.notify();
+            return;
+        }
+        let port = port.expect("validated port");
+        let endpoint = format!("{host}:{port}");
+        self.testing_connection = true;
+        self.connection_test_result = None;
+        cx.notify();
+        cx.spawn(async move |this, cx| {
+            let result = cx
+                .background_executor()
+                .spawn(async move { probe_ssh_service(&host, port) })
+                .await;
+            this.update_in(cx, |this, _, cx| {
+                this.testing_connection = false;
+                this.connection_test_result = Some(match result {
+                    Ok(()) => (
+                        true,
+                        format!("{endpoint}：SSH 服务可达，尚未验证登录认证").into(),
+                    ),
+                    Err(error) => (false, format!("{endpoint}：{error}").into()),
+                });
+                cx.notify();
+            })
+            .ok();
+        })
+        .detach();
+    }
+
     /// Validate and write to the store. Returns whether the dialog may close.
     pub fn commit(&mut self, window: &mut Window, cx: &mut Context<Self>) -> bool {
         let name = self.name.read(cx).value().trim().to_string();
@@ -505,9 +555,67 @@ impl Render for SessionForm {
                         .child(error),
                 )
             })
+            .when_some(
+                self.connection_test_result.clone(),
+                |form, (success, message)| {
+                    form.child(
+                        div()
+                            .id("connection-test-result")
+                            .test_support()
+                            .aria_label(message.clone())
+                            .text_sm()
+                            .text_color(if success {
+                                cx.theme().success
+                            } else {
+                                cx.theme().danger
+                            })
+                            .child(message),
+                    )
+                },
+            )
     }
 }
 
+/// Check that a TCP endpoint speaks SSH. Authentication is intentionally not
+/// attempted, so the form can test unsaved hosts without storing credentials
+/// or changing the application's trusted-host list.
+fn probe_ssh_service(host: &str, port: u16) -> Result<(), String> {
+    let runtime = tokio::runtime::Builder::new_current_thread()
+        .enable_all()
+        .build()
+        .map_err(|error| format!("无法启动连接测试：{error}"))?;
+    runtime.block_on(async {
+        tokio::time::timeout(Duration::from_secs(8), async {
+            let mut stream = tokio::net::TcpStream::connect((host, port))
+                .await
+                .map_err(|error| format!("无法连接：{error}"))?;
+            stream
+                .write_all(b"SSH-2.0-shellr-probe\r\n")
+                .await
+                .map_err(|error| format!("无法发送 SSH 标识：{error}"))?;
+            for _ in 0..10 {
+                let mut line = Vec::new();
+                for _ in 0..255 {
+                    let byte = stream
+                        .read_u8()
+                        .await
+                        .map_err(|error| format!("无法读取 SSH 标识：{error}"))?;
+                    if byte == b'\n' {
+                        break;
+                    }
+                    line.push(byte);
+                }
+                if line.starts_with(b"SSH-2.0-") || line.starts_with(b"SSH-1.99-") {
+                    return Ok(());
+                }
+            }
+            Err("目标端口没有返回 SSH 服务标识".to_string())
+        })
+        .await
+        .map_err(|_| "连接超时".to_string())?
+    })
+}
+
 /// Open the new-session (`editing == None`) or edit-session dialog.
 /// `preselect_group` fills in the group field of a new session, so creating
 /// one from a group's context menu lands it in that group.
@@ -556,16 +664,49 @@ pub fn open_session_dialog(
 
     window.open_dialog(cx, {
         let form = form.clone();
-        move |dialog, _, _| {
+        move |dialog, _, cx| {
             dialog
                 .title(title.clone())
                 .child(form.clone())
                 .footer(
                     DialogFooter::new()
-                        .child(DialogClose::new().trigger(|button| button.label("取消")))
+                        .w_full()
+                        .justify_between()
                         .child(
-                            DialogAction::new()
-                                .child(Button::new("commit").primary().label(commit_label.clone())),
+                            Button::new("test-connection")
+                                .label("测试连接")
+                                .icon(crate::app::CatalogIcon::Plug)
+                                .small()
+                                .loading(form.read(cx).testing_connection)
+                                .on_click({
+                                    let form = form.clone();
+                                    move |event, window, cx| {
+                                        form.update(cx, |form, cx| {
+                                            form.test_connection(event, window, cx)
+                                        });
+                                    }
+                                }),
+                        )
+                        .child(
+                            h_flex()
+                                .gap_2()
+                                .child(Button::new("cancel").label("取消").small().on_click(
+                                    |_, window, cx| {
+                                        window.dispatch_action(Box::new(Cancel), cx);
+                                    },
+                                ))
+                                .child(
+                                    Button::new("commit")
+                                        .primary()
+                                        .label(commit_label.clone())
+                                        .small()
+                                        .on_click(|_, window, cx| {
+                                            window.dispatch_action(
+                                                Box::new(Confirm { secondary: false }),
+                                                cx,
+                                            );
+                                        }),
+                                ),
                         ),
                 )
                 .on_ok({
diff --git a/src/session/session_panel.rs b/src/session/session_panel.rs
index c99600b..fabbcfe 100644
--- a/src/session/session_panel.rs
+++ b/src/session/session_panel.rs
@@ -21,9 +21,9 @@ use gpui_kit::prelude::FluentBuilder as _;
 use gpui_kit::*;
 
 use crate::app::{
-    CatalogIcon, ConnectSelected, ConnectSession, DeleteGroup, DeleteSession, DuplicateSession,
-    EditSession, MoveSessionNode, NewChildGroup, NewGroup, NewSession, NewSessionInGroup,
-    OpenExplorer, RenameGroup, SESSION_PANEL_CONTEXT,
+    CatalogIcon, CollapseAllGroups, ConnectGroup, ConnectSelected, ConnectSession, DeleteGroup,
+    DeleteSession, DuplicateSession, EditSession, ExpandAllGroups, MoveSessionNode, NewChildGroup,
+    NewGroup, NewSession, NewSessionInGroup, OpenExplorer, RenameGroup, SESSION_PANEL_CONTEXT,
 };
 
 use crate::shared::HostMark;
@@ -271,6 +271,22 @@ impl SessionPanel {
         self.search.update(cx, |input, cx| input.focus(window, cx));
     }
 
+    /// Refresh the visible tree after a bulk expansion change in the store.
+    pub fn set_all_groups_expanded(&mut self, expanded: bool, cx: &mut Context<Self>) {
+        self.expanded = if expanded {
+            self.store
+                .read(cx)
+                .groups()
+                .iter()
+                .map(|group| group.id)
+                .collect()
+        } else {
+            HashSet::new()
+        };
+        self.right_clicked.set(None);
+        self.rebuild_tree(cx);
+    }
+
     /// The node currently selected in the tree.
     pub fn selected_node(&self, cx: &App) -> Option<SessionNode> {
         self.tree_state
@@ -789,6 +805,12 @@ fn build_context_menu(node: Option<SessionNode>, menu: PopupMenu) -> PopupMenu {
                 Box::new(DeleteSession(id)),
             ),
         Some(SessionNode::Group(id)) => menu
+            .menu_with_icon(
+                "连接组内主机",
+                Icon::new(CatalogIcon::Plug),
+                Box::new(ConnectGroup(id)),
+            )
+            .separator()
             .menu_with_icon(
                 "新建会话…",
                 Icon::new(IconName::Plus),
@@ -800,6 +822,17 @@ fn build_context_menu(node: Option<SessionNode>, menu: PopupMenu) -> PopupMenu {
                 Box::new(NewChildGroup(id)),
             )
             .separator()
+            .menu_with_icon(
+                "展开全部分组",
+                Icon::new(IconName::FolderOpen),
+                Box::new(ExpandAllGroups),
+            )
+            .menu_with_icon(
+                "折叠全部分组",
+                Icon::new(IconName::Folder),
+                Box::new(CollapseAllGroups),
+            )
+            .separator()
             .menu_with_icon(
                 "重命名分组…",
                 Icon::new(CatalogIcon::Pencil),
diff --git a/src/session/store.rs b/src/session/store.rs
index e8e3f1f..4253e7a 100644
--- a/src/session/store.rs
+++ b/src/session/store.rs
@@ -509,6 +509,25 @@ impl SessionStore {
         true
     }
 
+    /// Apply one expansion choice to the whole tree and persist it together.
+    pub fn set_all_groups_expanded(&mut self, expanded: bool, cx: &mut Context<Self>) -> bool {
+        if self.groups.iter().all(|group| group.expanded == expanded) {
+            return false;
+        }
+        for group in &mut self.groups {
+            group.expanded = expanded;
+        }
+        if let Some(database) = self.database.as_ref() {
+            self.report(
+                database.set_all_groups_expanded(expanded),
+                "保存所有分组展开状态",
+                cx,
+            );
+        }
+        cx.notify();
+        true
+    }
+
     /// Move a group or host in the tree and persist its new location and
     /// sibling order in one transaction.
     pub fn move_node(
diff --git a/src/workspace/recent_sessions.rs b/src/workspace/recent_sessions.rs
index eadd1cc..330e5ea 100644
--- a/src/workspace/recent_sessions.rs
+++ b/src/workspace/recent_sessions.rs
@@ -50,6 +50,13 @@ impl RecentSessions {
         }
     }
 
+    /// A newly shown start page begins without a selected host.
+    pub(super) fn clear_selection(&mut self, cx: &mut Context<Self>) {
+        if self.selected.take().is_some() {
+            cx.notify();
+        }
+    }
+
     fn rows(&self, cx: &App) -> Vec<RecentRow> {
         let store = self.store.read(cx);
         store
diff --git a/src/workspace/workspace_view.rs b/src/workspace/workspace_view.rs
index f78604d..e211f22 100644
--- a/src/workspace/workspace_view.rs
+++ b/src/workspace/workspace_view.rs
@@ -19,12 +19,13 @@ use gpui_kit::prelude::FluentBuilder as _;
 use gpui_kit::*;
 
 use crate::app::{
-    CloseActiveTab, CloseExplorer, CloseLocalTerminal, CloseTerminal, ConnectSession, CopyTerminal,
-    DeleteGroup, DeleteSession, DisconnectSession, DuplicateSession, EditSession, ExplorerAction,
-    ExplorerCommand, FocusSearch, MoveSessionNode, NewChildGroup, NewGroup, NewLocalTerminal,
-    NewSession, NewSessionInGroup, OpenExplorer, PasteTerminal, ReconnectTerminal, RenameGroup,
-    RestartLocalTerminal, SelectAllUploadFiles, ToggleSessionPanel, ToggleTheme,
-    ToggleUploadSelection, UploadSelectedFiles, ZoomIn, ZoomOut, ZoomReset,
+    CloseActiveTab, CloseExplorer, CloseLocalTerminal, CloseTerminal, CollapseAllGroups,
+    ConnectGroup, ConnectSession, CopyTerminal, DeleteGroup, DeleteSession, DisconnectSession,
+    DuplicateSession, EditSession, ExpandAllGroups, ExplorerAction, ExplorerCommand, FocusSearch,
+    MoveSessionNode, NewChildGroup, NewGroup, NewLocalTerminal, NewSession, NewSessionInGroup,
+    OpenExplorer, PasteTerminal, ReconnectTerminal, RenameGroup, RestartLocalTerminal,
+    SelectAllUploadFiles, ToggleSessionPanel, ToggleTheme, ToggleUploadSelection,
+    UploadSelectedFiles, ZoomIn, ZoomOut, ZoomReset,
 };
 use crate::explorer::{ExplorerPanel, ExplorerPanelEvent, confirm_close_upload};
 use crate::session::{
@@ -352,6 +353,8 @@ impl Workspace {
         let was_empty = self.skin.is_center_empty();
         self.skin.set_center_empty(empty, cx);
         if empty && !was_empty {
+            self.recent
+                .update(cx, |recent, cx| recent.clear_selection(cx));
             let page = self.recent.read(cx).focus_handle(cx);
             window.focus(&page, cx);
         }
@@ -751,7 +754,27 @@ impl Workspace {
         window: &mut Window,
         cx: &mut Context<Self>,
     ) {
-        let session_id = action.0;
+        self.connect_session(action.0, window, cx);
+    }
+
+    fn on_connect_group(
+        &mut self,
+        action: &ConnectGroup,
+        window: &mut Window,
+        cx: &mut Context<Self>,
+    ) {
+        let session_ids = self.store.read(cx).sessions_under(action.0);
+        for session_id in session_ids {
+            self.connect_session(session_id, window, cx);
+        }
+    }
+
+    fn connect_session(
+        &mut self,
+        session_id: SessionId,
+        window: &mut Window,
+        cx: &mut Context<Self>,
+    ) {
         if self.store.read(cx).session(session_id).is_none() {
             return;
         }
@@ -1153,6 +1176,31 @@ impl Workspace {
         open_group_dialog(None, None, self.store.clone(), window, cx);
     }
 
+    fn on_expand_all_groups(
+        &mut self,
+        _: &ExpandAllGroups,
+        _: &mut Window,
+        cx: &mut Context<Self>,
+    ) {
+        self.set_all_groups_expanded(true, cx);
+    }
+
+    fn on_collapse_all_groups(
+        &mut self,
+        _: &CollapseAllGroups,
+        _: &mut Window,
+        cx: &mut Context<Self>,
+    ) {
+        self.set_all_groups_expanded(false, cx);
+    }
+
+    fn set_all_groups_expanded(&mut self, expanded: bool, cx: &mut Context<Self>) {
+        self.store
+            .update(cx, |store, cx| store.set_all_groups_expanded(expanded, cx));
+        self.session_panel
+            .update(cx, |panel, cx| panel.set_all_groups_expanded(expanded, cx));
+    }
+
     fn on_new_child_group(
         &mut self,
         action: &NewChildGroup,
@@ -1517,10 +1565,13 @@ impl Render for Workspace {
             .on_action(cx.listener(Self::on_delete_session))
             .on_action(cx.listener(Self::on_new_session_in_group))
             .on_action(cx.listener(Self::on_new_group))
+            .on_action(cx.listener(Self::on_expand_all_groups))
+            .on_action(cx.listener(Self::on_collapse_all_groups))
             .on_action(cx.listener(Self::on_new_child_group))
             .on_action(cx.listener(Self::on_rename_group))
             .on_action(cx.listener(Self::on_delete_group))
             .on_action(cx.listener(Self::on_connect_session))
+            .on_action(cx.listener(Self::on_connect_group))
             .on_action(cx.listener(Self::on_disconnect_session))
             .on_action(cx.listener(Self::on_reconnect_terminal))
             .on_action(cx.listener(Self::on_open_explorer))
diff --git a/tests/ui.rs b/tests/ui.rs
index 481fa05..e2ee642 100644
--- a/tests/ui.rs
+++ b/tests/ui.rs
@@ -1,6 +1,8 @@
 //! UI integration tests: the production `Workspace` rendered in a headless
 //! window, driven through real pointer and keyboard events.
 
+use std::io::Write as _;
+use std::net::TcpListener;
 use std::sync::atomic::{AtomicUsize, Ordering};
 use std::sync::{Arc, Mutex, mpsc};
 use std::time::Duration;
@@ -13,13 +15,13 @@ use gpui_kit::{
 };
 
 use shellr::app::{
-    ConnectSession, DeleteGroup, DeleteSession, EditSession, NewSessionInGroup, OpenExplorer,
-    RenameGroup,
+    CollapseAllGroups, ConnectGroup, ConnectSession, DeleteGroup, DeleteSession, EditSession,
+    ExpandAllGroups, NewSessionInGroup, OpenExplorer, RenameGroup,
 };
 use shellr::secrets::{InMemorySecretStore, SecretRef, SecretStore as _};
 use shellr::session::{
-    AuthKind, ConnectionState, GroupId, HostOs, SessionDatabase, SessionDraft, SessionId,
-    SessionStore,
+    AuthKind, ConnectionState, GroupDraft, GroupId, HostOs, SessionDatabase, SessionDraft,
+    SessionId, SessionStore,
 };
 use shellr::sftp::{
     DirectoryEntry, DirectoryListing, EntryKind, FileMetadata, LocalDirectoryProvider, RemotePath,
@@ -34,8 +36,10 @@ use shellr::workspace::Workspace;
 
 /// Seeded session ids, in insertion order (see `SessionStore::seed`).
 const WEB_01: u64 = 1;
+const WEB_02: u64 = 2;
 const DB_01: u64 = 3;
 const STAGING_API: u64 = 4;
+const DEV_BOX: u64 = 6;
 const INITIAL_WEB_TERMINAL: u64 = 1;
 const INITIAL_STAGING_TERMINAL: u64 = 2;
 const FIRST_NEW_TERMINAL: u64 = 3;
@@ -861,6 +865,72 @@ async fn new_session_dialog_validates_then_inserts(cx: &mut TestAppContext) {
     });
 }
 
+#[gpui_kit::test]
+async fn session_dialog_tests_ssh_service_without_saving(cx: &mut TestAppContext) {
+    let listener = TcpListener::bind(("127.0.0.1", 0)).unwrap();
+    let port = listener.local_addr().unwrap().port();
+    let (reply, resume) = mpsc::channel();
+    let server = std::thread::spawn(move || {
+        let (mut stream, _) = listener.accept().unwrap();
+        resume.recv_timeout(Duration::from_secs(3)).unwrap();
+        stream.write_all(b"SSH-2.0-test-server\r\n").unwrap();
+    });
+    let (handle, workspace) = open_workspace_with_store(cx, SessionStore::empty());
+
+    cx.update_window(handle.into(), |_, window, cx| {
+        window.render_frame(cx);
+        window.click("new-session", cx);
+    })
+    .unwrap();
+    cx.run_until_parked();
+    cx.update_window(handle.into(), |_, window, cx| {
+        window.render_frame(cx);
+        let test = window.find("test-connection").bounds();
+        let cancel = window.find("cancel").bounds();
+        let commit = window.find("commit").bounds();
+        assert!(test.right() < cancel.left());
+        assert!(cancel.right() < commit.left());
+        assert!(commit.size.width < window.find("session-host").bounds().size.width);
+
+        window.click("test-connection", cx);
+    })
+    .unwrap();
+    cx.update_window(handle.into(), |_, window, cx| {
+        window.render_frame(cx);
+        assert_eq!(
+            window.find("connection-test-result").label(),
+            Some("请输入主机")
+        );
+        window.click("session-host", cx);
+        window.input("127.0.0.1", cx);
+        window.click("session-port", cx);
+        #[cfg(target_os = "macos")]
+        window.press("cmd-a", cx);
+        #[cfg(not(target_os = "macos"))]
+        window.press("ctrl-a", cx);
+        window.input(&port.to_string(), cx);
+        window.click("test-connection", cx);
+    })
+    .unwrap();
+    cx.update_window(handle.into(), |_, window, cx| {
+        window.render_frame(cx);
+        assert!(window.find("test-connection").visible());
+        assert!(window.try_find("connection-test-result").is_none());
+    })
+    .unwrap();
+    reply.send(()).unwrap();
+    cx.wait_for(handle.into(), Duration::from_secs(3), |window, cx| {
+        window.render_frame(cx);
+        window
+            .try_find("connection-test-result")
+            .and_then(|result| result.label().map(str::to_string))
+            .is_some_and(|message| message.contains("SSH 服务可达"))
+    })
+    .await;
+    server.join().unwrap();
+    cx.update(|cx| assert!(workspace.read(cx).store().read(cx).sessions().is_empty()));
+}
+
 #[gpui_kit::test]
 fn search_filters_the_tree(cx: &mut TestAppContext) {
     let (handle, _) = open_workspace(cx);
@@ -954,6 +1024,123 @@ fn group_expansion_survives_reopening_the_database(cx: &mut TestAppContext) {
     );
 }
 
+#[gpui_kit::test]
+fn expand_and_collapse_all_groups_include_nested_groups_and_persist(cx: &mut TestAppContext) {
+    let dir = tempfile::tempdir().unwrap();
+    let path = dir.path().join("shellr.db");
+    let database = SessionDatabase::open(&path).unwrap();
+    let mut seed = SessionStore::seed();
+    let nested =
+        seed.insert_group_unnotified(GroupDraft::new("内部服务", Some(GroupId(PRODUCTION))));
+    for group in seed.groups() {
+        database.insert_group(group).unwrap();
+    }
+    for session in seed.sessions() {
+        database.insert_session(session).unwrap();
+    }
+    let (handle, _) = open_workspace_with_store(cx, SessionStore::load(database).unwrap());
+
+    cx.update_window(handle.into(), |_, window, cx| {
+        window.render_frame(cx);
+        assert!(window.find(("group-row", nested.0)).visible());
+        assert!(window.find(("session-row", WEB_01)).visible());
+        window.dispatch_action(Box::new(CollapseAllGroups), cx);
+    })
+    .unwrap();
+    cx.run_until_parked();
+    cx.update_window(handle.into(), |_, window, cx| {
+        window.render_frame(cx);
+        assert!(window.find(("group-row", PRODUCTION)).visible());
+        assert!(window.try_find(("group-row", nested.0)).is_none());
+        assert!(window.try_find(("session-row", WEB_01)).is_none());
+    })
+    .unwrap();
+    assert!(
+        SessionDatabase::open(&path)
+            .unwrap()
+            .load()
+            .unwrap()
+            .groups
+            .iter()
+            .all(|group| !group.expanded)
+    );
+
+    cx.update_window(handle.into(), |_, window, cx| {
+        window.dispatch_action(Box::new(ExpandAllGroups), cx);
+    })
+    .unwrap();
+    cx.run_until_parked();
+    cx.update_window(handle.into(), |_, window, cx| {
+        window.render_frame(cx);
+        assert!(window.find(("group-row", nested.0)).visible());
+        assert!(window.find(("session-row", WEB_01)).visible());
+    })
+    .unwrap();
+    let database = SessionDatabase::open(&path).unwrap();
+    assert!(
+        database
+            .load()
+            .unwrap()
+            .groups
+            .iter()
+            .all(|group| group.expanded)
+    );
+    let (reopened, _) = open_workspace_with_store(cx, SessionStore::load(database).unwrap());
+    cx.update_window(reopened.into(), |_, window, cx| {
+        window.render_frame(cx);
+        assert!(window.find(("group-row", nested.0)).visible());
+        assert!(window.find(("session-row", WEB_01)).visible());
+    })
+    .unwrap();
+}
+
+#[gpui_kit::test]
+fn connect_group_opens_each_host_in_its_subtree(cx: &mut TestAppContext) {
+    let mut store = SessionStore::seed();
+    let child =
+        store.insert_group_unnotified(GroupDraft::new("内部服务", Some(GroupId(PRODUCTION))));
+    let grandchild = store.insert_group_unnotified(GroupDraft::new("后端", Some(child)));
+    let nested_host = store.insert_unnotified(SessionDraft::new(
+        "backend-01",
+        "10.0.3.8",
+        22,
+        "deploy",
+        AuthKind::Auto,
+        Some(grandchild),
+    ));
+    let (handle, workspace) = open_workspace_with_store(cx, store);
+
+    cx.update_window(handle.into(), |_, window, cx| {
+        window.render_frame(cx);
+        window.dispatch_action(Box::new(ConnectGroup(child)), cx);
+    })
+    .unwrap();
+    cx.run_until_parked();
+    cx.update(|cx| {
+        let workspace = workspace.read(cx);
+        assert_eq!(workspace.terminal_count(nested_host, cx), 1);
+        assert_eq!(workspace.terminal_count(SessionId(WEB_01), cx), 1);
+        assert_eq!(workspace.terminal_count(SessionId(DB_01), cx), 0);
+        assert_eq!(workspace.terminal_count(SessionId(STAGING_API), cx), 1);
+    });
+
+    cx.update_window(handle.into(), |_, window, cx| {
+        window.render_frame(cx);
+        window.dispatch_action(Box::new(ConnectGroup(GroupId(PRODUCTION))), cx);
+    })
+    .unwrap();
+    cx.run_until_parked();
+    cx.update(|cx| {
+        let workspace = workspace.read(cx);
+        assert_eq!(workspace.terminal_count(nested_host, cx), 2);
+        assert_eq!(workspace.terminal_count(SessionId(WEB_01), cx), 2);
+        assert_eq!(workspace.terminal_count(SessionId(WEB_02), cx), 1);
+        assert_eq!(workspace.terminal_count(SessionId(DB_01), cx), 1);
+        assert_eq!(workspace.terminal_count(SessionId(STAGING_API), cx), 1);
+        assert_eq!(workspace.terminal_count(SessionId(DEV_BOX), cx), 0);
+    });
+}
+
 #[gpui_kit::test]
 fn dragging_a_host_into_a_group_updates_the_session_tree(cx: &mut TestAppContext) {
     let (handle, workspace) = open_workspace(cx);
@@ -1312,6 +1499,32 @@ async fn closing_every_tab_shows_the_recent_sessions(cx: &mut TestAppContext) {
         // Reconnecting moved web-01 to the front.
         assert_eq!(recent, ["web-01", "staging-api"]);
     });
+
+    cx.update_window(handle.into(), |_, window, cx| {
+        window.render_frame(cx);
+        window.click(("close-terminal", FIRST_NEW_TERMINAL), cx);
+    })
+    .unwrap();
+    cx.run_until_parked();
+
+    cx.update_window(handle.into(), |_, window, cx| {
+        window.render_frame(cx);
+        assert!(window.find("recent-sessions").visible());
+        // Reopening the page must not reconnect the old selection on Enter.
+        window.press("enter", cx);
+    })
+    .unwrap();
+    cx.run_until_parked();
+    cx.update_window(handle.into(), |_, window, cx| {
+        window.render_frame(cx);
+        assert!(window.find("recent-sessions").visible());
+        assert!(
+            window
+                .try_find(("terminal", FIRST_NEW_TERMINAL + 1))
+                .is_none()
+        );
+    })
+    .unwrap();
 }
 
 #[gpui_kit::test]