refactor(shell): own window interaction state

crates/nyaterm-desktop/src/features/app_state/construct.rs

@@ -1,9 +1,9 @@
 use crate::models::{
-    ActivityBarLayoutState, BottomPanelMode, HeaderStatusState, MainMode, NavItem, PanelSide,
-    RightFocus, SessionEventBridge, SettingsTab, StoreStatus, TerminalFramePipeline,
+    ActivityBarLayoutState, BottomPanelMode, NavItem, PanelSide, SessionEventBridge, StoreStatus,
+    TerminalFramePipeline,
 };
 use crate::terminal::initial_terminal_screen;
-use gpui::{Context, ScrollHandle};
+use gpui::Context;
 use nyaterm_core::{
     AiSettings, AppRuntime, AppSettingsSummary, CLOUD_SYNC_HISTORY_LIMIT, CloudSyncSettings,
     CloudSyncState, ConnectionStore, KeywordHighlightConfig, NativeServices, TranslationSettings,
@@ -11,7 +11,7 @@ use nyaterm_core::{
 };
 use nyaterm_terminal::TerminalOutputDecoder;
 use nyaterm_transport::{SessionManager, SftpDuplicatePolicy};
-use std::collections::{HashMap, HashSet, VecDeque};
+use std::collections::{HashMap, VecDeque};
 use std::sync::Arc;
 
 use super::super::settings::{SettingsFeatureFocus, SettingsFeatureState};
@@ -21,10 +21,10 @@ use super::super::{
     QuickCommandFeatureFocus, QuickCommandFeatureState, RecordingFeatureState,
     RemoteOpsFeatureFocus, RemoteOpsFeatureState, SecurityFeatureFocus, SecurityFeatureState,
     SendCommandFeatureFocus, SendCommandFeatureState, SessionFeatureFocus, SessionFeatureState,
-    ShellFeatureState, SyncInputFeatureState, TerminalFeatureFocus, TerminalFeatureState,
-    TextInputRegistry, TransferFeatureFocus, TransferFeatureState, TranslationFeatureState,
-    TunnelFeatureState, UpdateFeatureState, ai_active_profile_drafts, ai_usage_counts,
-    appearance_font_options, quick_command_sort_mode_from_setting,
+    ShellFeatureInit, ShellFeatureState, SyncInputFeatureState, TerminalFeatureFocus,
+    TerminalFeatureState, TextInputRegistry, TransferFeatureFocus, TransferFeatureState,
+    TranslationFeatureState, TunnelFeatureState, UpdateFeatureState, ai_active_profile_drafts,
+    ai_usage_counts, appearance_font_options, quick_command_sort_mode_from_setting,
     quick_command_view_mode_from_setting, spawn_command_persistence_worker,
 };
 use super::NyaTermApp;
@@ -444,17 +444,28 @@ impl NyaTermApp {
                 },
             ),
             text_inputs: TextInputRegistry::default(),
-            shell: ShellFeatureState::new(
-                if settings.ui_serial_send_visible {
+            shell: ShellFeatureState::new(ShellFeatureInit {
+                bottom_panel_mode: if settings.ui_serial_send_visible {
                     BottomPanelMode::CommandSend
                 } else if settings.ui_quick_cmd_visible {
                     BottomPanelMode::QuickCommands
                 } else {
                     BottomPanelMode::Hidden
                 },
-                quick_cmd_height,
-                serial_send_height,
-            ),
+                quick_commands_height: quick_cmd_height,
+                command_send_height: serial_send_height,
+                active_left_panel,
+                active_right_panel,
+                left_open_panels,
+                right_open_panels,
+                panel_stack_sizes,
+                panel_multi_open,
+                left_sidebar_collapsed,
+                right_inspector_collapsed,
+                left_panel_width,
+                right_panel_width,
+                activity_bar_layout,
+            }),
             sync_input: SyncInputFeatureState::new(cx.focus_handle()),
             keyword_highlights,
             settings,
@@ -472,53 +483,6 @@ impl NyaTermApp {
             active_snapshot_password_prompt: None,
             pending_session_events: VecDeque::new(),
             diagnostic_log_last_at: HashMap::new(),
-            last_viewport_size: (1280., 800.),
-            wallpaper_tile_dimensions: None,
-            last_viewport_change_at: None,
-            title_drag_active_until: None,
-            selected_nav: NavItem::Workspace,
-            main_mode: MainMode::Workspace,
-            settings_active_tab: SettingsTab::General,
-            settings_expanded_groups: HashSet::from(["workspace".to_string()]),
-            settings_draft_snapshot: None,
-            settings_window: None,
-            settings_window_open_pending: false,
-            settings_previous_left_collapsed: None,
-            settings_previous_right_collapsed: None,
-            active_left_panel,
-            active_right_panel,
-            left_open_panels,
-            right_open_panels,
-            panel_stack_sizes,
-            panel_multi_open,
-            right_focus: RightFocus::Default,
-            left_sidebar_collapsed,
-            right_inspector_collapsed,
-            mobile_left_open: false,
-            mobile_right_open: false,
-            left_panel_width,
-            right_panel_width,
-            panel_resize: None,
-            panel_stack_resize: None,
-            activity_bar_layout,
-            activity_bar_context_menu: None,
-            title_menu_open: None,
-            title_menu_submenu: None,
-            header_status: HeaderStatusState::default(),
-            open_tabs_menu_open: false,
-            new_session_menu_open: false,
-            new_session_all_sessions_open: false,
-            new_session_group_menu_path: Vec::new(),
-            session_tab_strip_scroll: ScrollHandle::new(),
-            session_tab_scroll_into_view_pending: false,
-            last_connect_failure_name: None,
-            last_connect_failure_error: None,
-            workspace_split: None,
-            workspace_split_resize: None,
-            session_pane_roots: HashMap::new(),
-            session_tab_owner: HashMap::new(),
-            focused_terminal_window_leaf_id: None,
-            workspace_pane_layout_restored: false,
             startup_restore_complete: false,
         }
     }

crates/nyaterm-desktop/src/features/app_state/mod.rs

@@ -1,8 +1,8 @@
-use std::collections::{HashMap, HashSet, VecDeque};
+use std::collections::{HashMap, VecDeque};
 use std::sync::{Arc, mpsc};
 use std::time::Instant;
 
-use gpui::{ScrollHandle, WindowHandle};
+use gpui::WindowHandle;
 use nyaterm_core::{
     AppRuntime, AppSettingsSummary, CommandHistoryEntry, Group, KeywordHighlightConfig,
     NativeServices, OtpEntry, ProxyConfig, ProxyGroup, QuickCommand, QuickCommandCategory,
@@ -21,7 +21,6 @@ use super::remote_editor_window::RemoteFileEditorWindow;
 use super::runtime_jobs::{CommandPersistenceRequest, CommandPersistenceResult};
 use super::session::SessionFeatureState;
 use super::settings::{SecurityFeatureState, SettingsFeatureState};
-use super::settings_window::SettingsWindow;
 use super::shell::ShellFeatureState;
 use super::sync::CloudSyncFeatureState;
 use super::sync_input::SyncInputFeatureState;
@@ -32,11 +31,8 @@ use super::translation::TranslationFeatureState;
 use super::tunnels::TunnelFeatureState;
 use super::update::UpdateFeatureState;
 use crate::models::{
-    ActivityBarContextMenuState, ActivityBarLayoutState, ConfigPathPromptKind,
-    DiagnosticsPathPromptKind, HeaderStatusState, KeywordHighlightPathPromptKind, MainMode,
-    NavItem, PanelResizeState, PanelStackResizeState, RightFocus, SettingsTab,
-    SnapshotPasswordPromptState, StoreStatus, TitleMenu, TitleMenuSubmenu, WorkspacePaneNode,
-    WorkspaceSplitResizeState, WorkspaceSplitState,
+    ConfigPathPromptKind, DiagnosticsPathPromptKind, KeywordHighlightPathPromptKind,
+    SnapshotPasswordPromptState, StoreStatus,
 };
 
 mod construct;
@@ -104,70 +100,5 @@ pub struct NyaTermApp {
     pub(in crate::features) active_snapshot_password_prompt: Option<SnapshotPasswordPromptState>,
     pub(in crate::features) pending_session_events: VecDeque<SessionEvent>,
     pub(in crate::features) diagnostic_log_last_at: HashMap<&'static str, Instant>,
-    pub(in crate::features) last_viewport_size: (f32, f32),
-    /// Cached intrinsic dimensions for the current tiled wallpaper path.
-    pub(in crate::features) wallpaper_tile_dimensions: Option<(String, u32, u32)>,
-    /// When the window viewport last changed (resize/drag geometry).
-    pub(in crate::features) last_viewport_change_at: Option<Instant>,
-    /// Deadline for treating title-bar window dragging as active.
-    pub(in crate::features) title_drag_active_until: Option<Instant>,
-    pub(in crate::features) selected_nav: NavItem,
-    pub(in crate::features) main_mode: MainMode,
-    pub(in crate::features) settings_active_tab: SettingsTab,
-    /// Expanded multi-item groups in the settings sidebar (Tauri keeps this local to the page).
-    pub(in crate::features) settings_expanded_groups: HashSet<String>,
-    /// Committed values captured when the in-window settings page opens.
-    pub(in crate::features) settings_draft_snapshot: Option<SettingsDraftSnapshot>,
-    pub(in crate::features) settings_window: Option<WindowHandle<SettingsWindow>>,
-    pub(in crate::features) settings_window_open_pending: bool,
-    /// Main workspace panel state to restore after leaving the in-window settings page.
-    pub(in crate::features) settings_previous_left_collapsed: Option<bool>,
-    pub(in crate::features) settings_previous_right_collapsed: Option<bool>,
-    pub(in crate::features) active_left_panel: Option<NavItem>,
-    pub(in crate::features) active_right_panel: Option<NavItem>,
-    pub(in crate::features) left_open_panels: Vec<String>,
-    pub(in crate::features) right_open_panels: Vec<String>,
-    pub(in crate::features) panel_stack_sizes: HashMap<String, f32>,
-    pub(in crate::features) panel_multi_open: bool,
-    pub(in crate::features) right_focus: RightFocus,
-    pub(in crate::features) left_sidebar_collapsed: bool,
-    pub(in crate::features) right_inspector_collapsed: bool,
-    pub(in crate::features) mobile_left_open: bool,
-    pub(in crate::features) mobile_right_open: bool,
-    pub(in crate::features) left_panel_width: f32,
-    pub(in crate::features) right_panel_width: f32,
-    pub(in crate::features) panel_resize: Option<PanelResizeState>,
-    pub(in crate::features) panel_stack_resize: Option<PanelStackResizeState>,
-    pub(in crate::features) activity_bar_layout: ActivityBarLayoutState,
-    pub(in crate::features) activity_bar_context_menu: Option<ActivityBarContextMenuState>,
-    pub(in crate::features) title_menu_open: Option<TitleMenu>,
-    pub(in crate::features) title_menu_submenu: Option<TitleMenuSubmenu>,
-    pub(in crate::features) header_status: HeaderStatusState,
-    /// Open-tabs overflow menu (Tauri TabBar expand-more when many tabs).
-    pub(in crate::features) open_tabs_menu_open: bool,
-    /// New-session menu next to the tab strip + control.
-    pub(in crate::features) new_session_menu_open: bool,
-    /// Whether the Tauri-style "All sessions" submenu is expanded.
-    pub(in crate::features) new_session_all_sessions_open: bool,
-    /// Hovered group ids from the root submenu through the deepest open child menu.
-    pub(in crate::features) new_session_group_menu_path: Vec<String>,
-    /// Horizontal scroll handle for the global session tab strip (scroll-into-view).
-    pub(in crate::features) session_tab_strip_scroll: ScrollHandle,
-    /// Request scroll-into-view of the active tab on next paint (Tauri TabBar).
-    pub(in crate::features) session_tab_scroll_into_view_pending: bool,
-    /// Last failed connect name (shown as ephemeral failed tab chrome).
-    pub(in crate::features) last_connect_failure_name: Option<String>,
-    /// Last failed connect error text.
-    pub(in crate::features) last_connect_failure_error: Option<String>,
-    /// Legacy/global active pane tree view: mirrors the active tab's per-tab root when split.
-    pub(in crate::features) workspace_split: Option<WorkspaceSplitState>,
-    pub(in crate::features) workspace_split_resize: Option<WorkspaceSplitResizeState>,
-    /// Per-tab pane trees keyed by tab-root session id (Tauri `Tab.root`).
-    pub(in crate::features) session_pane_roots: HashMap<String, WorkspacePaneNode>,
-    /// Leaf session id → owning tab-root session id (hidden from tab strip when secondary).
-    pub(in crate::features) session_tab_owner: HashMap<String, String>,
-    pub(in crate::features) focused_terminal_window_leaf_id: Option<String>,
-    /// Whether we already attempted startup restore of global workspace pane splits.
-    pub(in crate::features) workspace_pane_layout_restored: bool,
     pub(in crate::features) startup_restore_complete: bool,
 }

crates/nyaterm-desktop/src/features/commands/command_runtime/suggestions.rs

@@ -1154,7 +1154,7 @@ impl NyaTermApp {
             insets.left,
             insets.top,
             self.terminal_gutter_width_px_for_session(session_id),
-            self.last_viewport_size,
+            self.shell.viewport.size,
             cursor_row,
             cursor_col,
             menu_w,

crates/nyaterm-desktop/src/features/connections/connection_import_runtime.rs

@@ -47,8 +47,8 @@ impl NyaTermApp {
 
         self.connection_state.open_import_dialog();
         self.connection_state.close_list_more_menu();
-        self.title_menu_open = None;
-        self.title_menu_submenu = None;
+        self.shell.chrome.title_menu_open = None;
+        self.shell.chrome.title_menu_submenu = None;
         self.terminal.view.status = "select a connection import source".to_string();
         let import_focus = self.connection_state.import_focus_handle();
         window.focus(&import_focus);

crates/nyaterm-desktop/src/features/connections/connections/menus.rs

@@ -185,8 +185,8 @@ impl NyaTermApp {
     ) -> bool {
         if self.saved_connection_start_is_pending_or_queued(&connection) {
             self.terminal.view.status = format!("{} is already queued", connection.name);
-            self.selected_nav = NavItem::Workspace;
-            self.main_mode = MainMode::Workspace;
+            self.shell.navigation.selected_nav = NavItem::Workspace;
+            self.shell.navigation.main_mode = MainMode::Workspace;
             cx.notify();
             return false;
         }
@@ -200,8 +200,8 @@ impl NyaTermApp {
             "queued {name} ({} pending)",
             self.pending_saved_connection_queue.len()
         );
-        self.selected_nav = NavItem::Workspace;
-        self.main_mode = MainMode::Workspace;
+        self.shell.navigation.selected_nav = NavItem::Workspace;
+        self.shell.navigation.main_mode = MainMode::Workspace;
         cx.notify();
         true
     }

crates/nyaterm-desktop/src/features/inspector/ai_ask.rs

@@ -687,7 +687,7 @@ impl NyaTermApp {
                                                                     |this, _, _, cx| {
                                                                         this.ai.discovery.menu_open =
                                                                             false;
-                                                                        this.settings_active_tab =
+                                                                        this.shell.navigation.settings.active_tab =
                                                                             SettingsTab::AiModels;
                                                                         this.open_page(
                                                                             NavItem::Settings,

crates/nyaterm-desktop/src/features/inspector/ai_widgets/messages.rs

@@ -86,7 +86,7 @@ impl NyaTermApp {
             });
         let quote_text = state.text.clone();
         let copy_text = state.text.clone();
-        let (viewport_w, viewport_h) = self.last_viewport_size;
+        let (viewport_w, viewport_h) = self.shell.viewport.size;
         let (menu_x, menu_y, menu_max_h) = ai_message_menu_position(
             f32::from(state.x),
             f32::from(state.y),

crates/nyaterm-desktop/src/features/inspector/ai_widgets/transcript.rs

@@ -112,7 +112,7 @@ impl NyaTermApp {
                         .cursor_pointer()
                         .hover(|this| this.bg(rgb(0x2ea043)))
                         .on_click(cx.listener(|this, _, _, cx| {
-                            this.settings_active_tab = SettingsTab::AiGeneral;
+                            this.shell.navigation.settings.active_tab = SettingsTab::AiGeneral;
                             this.open_page(NavItem::Settings, cx);
                         }))
                         .child(self.tr("ai.setupAction")),

crates/nyaterm-desktop/src/features/inspector/right_shell.rs

@@ -9,9 +9,9 @@ impl NyaTermApp {
         window: &mut gpui::Window,
         cx: &mut Context<Self>,
     ) -> impl IntoElement {
-        let mut width = self.right_panel_width.clamp(200., 720.);
-        if !cfg!(target_os = "macos") && self.last_viewport_size.0 < 768. {
-            width = width.min((self.last_viewport_size.0 - 80.).max(120.));
+        let mut width = self.shell.panels.right_width.clamp(200., 720.);
+        if !cfg!(target_os = "macos") && self.shell.viewport.size.0 < 768. {
+            width = width.min((self.shell.viewport.size.0 - 80.).max(120.));
         }
         let palette = self.theme_palette();
         div()

crates/nyaterm-desktop/src/features/layout/activity_bar.rs

@@ -15,12 +15,12 @@ impl NyaTermApp {
         cx: &mut Context<Self>,
     ) -> impl IntoElement {
         let palette = self.theme_palette();
-        let Some(menu) = self.activity_bar_context_menu.clone() else {
+        let Some(menu) = self.shell.chrome.activity_bar_context_menu.clone() else {
             return div().into_any_element();
         };
         let entry_id = menu.entry_id.clone();
-        let show_labels = self.activity_bar_layout.show_labels;
-        let (viewport_w, viewport_h) = self.last_viewport_size;
+        let show_labels = self.shell.chrome.activity_bar_layout.show_labels;
+        let (viewport_w, viewport_h) = self.shell.viewport.size;
         let menu_w = 180.;
         let submenu_w = 164.;
         let margin = 8.;
@@ -191,7 +191,7 @@ impl NyaTermApp {
         let bottom_entries = self.activity_entries_for_zone(bottom_zone);
         let top_len = top_entries.len();
         let bottom_len = bottom_entries.len();
-        let show_labels = self.activity_bar_layout.show_labels;
+        let show_labels = self.shell.chrome.activity_bar_layout.show_labels;
         let palette = self.theme_palette();
 
         // Tauri DropZone: gap-0.5 pt-1

crates/nyaterm-desktop/src/features/layout/prompts.rs

@@ -67,7 +67,7 @@ impl NyaTermApp {
             .child(
                 div()
                     .id("duplicate-prompt-dialog")
-                    .w(px((self.last_viewport_size.0 - 32.).min(448.).max(280.)))
+                    .w(px((self.shell.viewport.size.0 - 32.).min(448.).max(280.)))
                     .rounded_md()
                     .border_1()
                     .border_color(rgb(palette.border))
@@ -616,7 +616,7 @@ impl NyaTermApp {
                 prompt.id
             )))
             .w_full()
-            .max_h(px((self.last_viewport_size.1 - 32.).max(240.)))
+            .max_h(px((self.shell.viewport.size.1 - 32.).max(240.)))
             .overflow_y_scroll()
             .rounded_md()
             .border_1()

crates/nyaterm-desktop/src/features/layout/sidebar/shell.rs

@@ -9,9 +9,9 @@ impl NyaTermApp {
         window: &mut gpui::Window,
         cx: &mut Context<Self>,
     ) -> impl IntoElement {
-        let mut width = self.left_panel_width.clamp(160., 720.);
-        if !cfg!(target_os = "macos") && self.last_viewport_size.0 < 1024. {
-            width = width.min((self.last_viewport_size.0 - 80.).max(120.));
+        let mut width = self.shell.panels.left_width.clamp(160., 720.);
+        if !cfg!(target_os = "macos") && self.shell.viewport.size.0 < 1024. {
+            width = width.min((self.shell.viewport.size.0 - 80.).max(120.));
         }
         let palette = self.theme_palette();
         div()

crates/nyaterm-desktop/src/features/layout/title_bar/bar.rs

@@ -28,8 +28,8 @@ impl NyaTermApp {
         let palette = self.theme_palette();
         let macos = cfg!(target_os = "macos");
         let compact_layout = !cfg!(target_os = "macos");
-        let narrow_left = compact_layout && self.last_viewport_size.0 < 1024.;
-        let narrow_right = compact_layout && self.last_viewport_size.0 < 768.;
+        let narrow_left = compact_layout && self.shell.viewport.size.0 < 1024.;
+        let narrow_right = compact_layout && self.shell.viewport.size.0 < 768.;
         let header_status_visible = self.settings.ui_header_status_visible;
         let header_status = self.header_status_content();
         // Match Tauri Header: h-10.
@@ -207,7 +207,7 @@ impl NyaTermApp {
         cx: &mut Context<Self>,
     ) -> impl IntoElement {
         let palette = self.theme_palette();
-        let menu_open = self.header_status.menu_open;
+        let menu_open = self.shell.chrome.header_status.menu_open;
         let select_label = self.tr("headerStatus.select");
 
         div()
@@ -406,14 +406,14 @@ impl NyaTermApp {
     }
 
     pub(in crate::features) fn toggle_header_status_menu(&mut self, cx: &mut Context<Self>) {
-        self.header_status.menu_open = !self.header_status.menu_open;
-        if self.header_status.menu_open {
-            self.title_menu_open = None;
-            self.title_menu_submenu = None;
-            self.open_tabs_menu_open = false;
-            self.new_session_menu_open = false;
-            self.new_session_all_sessions_open = false;
-            self.new_session_group_menu_path.clear();
+        self.shell.chrome.header_status.menu_open = !self.shell.chrome.header_status.menu_open;
+        if self.shell.chrome.header_status.menu_open {
+            self.shell.chrome.title_menu_open = None;
+            self.shell.chrome.title_menu_submenu = None;
+            self.shell.chrome.open_tabs_menu_open = false;
+            self.shell.chrome.new_session_menu_open = false;
+            self.shell.chrome.new_session_all_sessions_open = false;
+            self.shell.chrome.new_session_group_menu_path.clear();
         }
         cx.notify();
     }
@@ -425,8 +425,8 @@ impl NyaTermApp {
     ) {
         self.settings.ui_header_status_mode = mode.persistence_id().to_string();
         self.settings.ui_header_status_visible = true;
-        self.header_status.menu_open = false;
-        self.header_status.rendered_minute = current_unix_minute();
+        self.shell.chrome.header_status.menu_open = false;
+        self.shell.chrome.header_status.rendered_minute = current_unix_minute();
         self.persist_header_status_settings();
         cx.notify();
     }
@@ -437,13 +437,13 @@ impl NyaTermApp {
         cx: &mut Context<Self>,
     ) {
         self.settings.ui_header_status_visible = visible;
-        self.header_status.menu_open = false;
+        self.shell.chrome.header_status.menu_open = false;
         self.persist_header_status_settings();
         cx.notify();
     }
 
     fn persist_header_status_settings(&mut self) {
-        if self.settings_draft_snapshot.is_some() {
+        if self.shell.navigation.settings.draft_snapshot.is_some() {
             self.terminal.view.status =
                 "header status changed; apply settings to persist".to_string();
         } else {
@@ -461,14 +461,14 @@ impl NyaTermApp {
         self.settings.ui_header_status_visible
             && HeaderStatusMode::from_setting(&self.settings.ui_header_status_mode)
                 == HeaderStatusMode::DateTime
-            && self.header_status.rendered_minute != current_unix_minute()
+            && self.shell.chrome.header_status.rendered_minute != current_unix_minute()
     }
 
     pub(in crate::features) fn refresh_header_status_clock(&mut self) -> bool {
         if !self.header_status_clock_refresh_due() {
             return false;
         }
-        self.header_status.rendered_minute = current_unix_minute();
+        self.shell.chrome.header_status.rendered_minute = current_unix_minute();
         true
     }
 
@@ -509,7 +509,7 @@ impl NyaTermApp {
         if let Some(failed) = self.failed_session_display_name() {
             return failed;
         }
-        if let Some(failed) = self.last_connect_failure_name.as_ref() {
+        if let Some(failed) = self.shell.chrome.last_connect_failure_name.as_ref() {
             return failed.clone();
         }
         "NyaTerm".to_string()
@@ -530,7 +530,8 @@ impl NyaTermApp {
         if self.has_pending_session_start() {
             return Some("icons/conn/connect.svg");
         }
-        if self.has_failed_session_start() || self.last_connect_failure_name.is_some() {
+        if self.has_failed_session_start() || self.shell.chrome.last_connect_failure_name.is_some()
+        {
             return Some("icons/session/disconnect.svg");
         }
         None
@@ -541,7 +542,7 @@ impl NyaTermApp {
         menu: TitleMenu,
         cx: &mut Context<Self>,
     ) -> impl IntoElement {
-        let open = self.title_menu_open == Some(menu);
+        let open = self.shell.chrome.title_menu_open == Some(menu);
         let id_label = menu.label();
         let label = self.tr(menu.i18n_key());
         let palette = self.theme_palette();
@@ -585,25 +586,25 @@ impl NyaTermApp {
         menu: TitleMenu,
         cx: &mut Context<Self>,
     ) {
-        self.title_menu_open = if self.title_menu_open == Some(menu) {
+        self.shell.chrome.title_menu_open = if self.shell.chrome.title_menu_open == Some(menu) {
             None
         } else {
             Some(menu)
         };
-        self.title_menu_submenu = None;
-        if self.title_menu_open.is_some() {
-            self.header_status.menu_open = false;
-            self.open_tabs_menu_open = false;
-            self.new_session_menu_open = false;
-            self.new_session_all_sessions_open = false;
-            self.new_session_group_menu_path.clear();
+        self.shell.chrome.title_menu_submenu = None;
+        if self.shell.chrome.title_menu_open.is_some() {
+            self.shell.chrome.header_status.menu_open = false;
+            self.shell.chrome.open_tabs_menu_open = false;
+            self.shell.chrome.new_session_menu_open = false;
+            self.shell.chrome.new_session_all_sessions_open = false;
+            self.shell.chrome.new_session_group_menu_path.clear();
         }
         cx.notify();
     }
 
     pub(in crate::features) fn close_title_menu(&mut self, cx: &mut Context<Self>) {
-        self.title_menu_submenu = None;
-        if self.title_menu_open.take().is_some() {
+        self.shell.chrome.title_menu_submenu = None;
+        if self.shell.chrome.title_menu_open.take().is_some() {
             cx.notify();
         }
     }
@@ -613,8 +614,8 @@ impl NyaTermApp {
         submenu: TitleMenuSubmenu,
         cx: &mut Context<Self>,
     ) {
-        if self.title_menu_submenu != Some(submenu) {
-            self.title_menu_submenu = Some(submenu);
+        if self.shell.chrome.title_menu_submenu != Some(submenu) {
+            self.shell.chrome.title_menu_submenu = Some(submenu);
             cx.notify();
         }
     }

crates/nyaterm-desktop/src/features/layout/title_bar/menu.rs

@@ -43,10 +43,10 @@ impl NyaTermApp {
                         Some(shortcut("tab.newSession", "Ctrl+Shift+N")),
                         cx.listener(|this, _, window, cx| {
                             this.close_title_menu(cx);
-                            this.open_tabs_menu_open = false;
-                            this.new_session_menu_open = false;
-                            this.new_session_all_sessions_open = false;
-                            this.new_session_group_menu_path.clear();
+                            this.shell.chrome.open_tabs_menu_open = false;
+                            this.shell.chrome.new_session_menu_open = false;
+                            this.shell.chrome.new_session_all_sessions_open = false;
+                            this.shell.chrome.new_session_group_menu_path.clear();
                             this.open_connection_editor(None, None, false, window, cx);
                         }),
                     ))
@@ -266,7 +266,7 @@ impl NyaTermApp {
             }
         }
 
-        items.when_some(self.title_menu_submenu, |this, submenu| {
+        items.when_some(self.shell.chrome.title_menu_submenu, |this, submenu| {
             this.child(self.title_menu_submenu(submenu, cx))
         })
     }
@@ -280,7 +280,7 @@ impl NyaTermApp {
         cx: &mut Context<Self>,
     ) -> impl IntoElement {
         let palette = self.theme_palette();
-        let open = self.title_menu_submenu == Some(submenu);
+        let open = self.shell.chrome.title_menu_submenu == Some(submenu);
         title_menu_submenu_trigger(
             palette,
             id,
@@ -293,10 +293,10 @@ impl NyaTermApp {
                 }
             }),
             cx.listener(move |this, _, _, cx| {
-                if this.title_menu_submenu == Some(submenu) {
-                    this.title_menu_submenu = None;
+                if this.shell.chrome.title_menu_submenu == Some(submenu) {
+                    this.shell.chrome.title_menu_submenu = None;
                 } else {
-                    this.title_menu_submenu = Some(submenu);
+                    this.shell.chrome.title_menu_submenu = Some(submenu);
                 }
                 cx.notify();
             }),

crates/nyaterm-desktop/src/features/layout/workspace/surface/empty.rs

@@ -151,7 +151,7 @@ impl NyaTermApp {
         let error = self
             .active_failed_session()
             .map(|failed| failed.error.clone())
-            .or_else(|| self.last_connect_failure_error.clone())
+            .or_else(|| self.shell.chrome.last_connect_failure_error.clone())
             .unwrap_or_default();
 
         div()

crates/nyaterm-desktop/src/features/layout/workspace/surface/menus.rs

@@ -165,7 +165,9 @@ impl NyaTermApp {
                     .as_deref()
                     .is_some_and(|id| self.tab_root_for_session(id) == session_id);
                 let leaf_ids = self
-                    .session_pane_roots
+                    .shell
+                    .workspace
+                    .pane_roots
                     .get(&session_id)
                     .map(|root| root.session_ids())
                     .unwrap_or_else(|| vec![session_id.clone()]);
@@ -282,7 +284,7 @@ impl NyaTermApp {
         let no_shell_sessions_label = self.tr("terminal.noShellSessions");
         let recent_sessions_label = self.tr("terminal.recentSessions");
         let no_recent_sessions_label = self.tr("terminal.noRecentSessions");
-        let all_sessions_open = self.new_session_all_sessions_open;
+        let all_sessions_open = self.shell.chrome.new_session_all_sessions_open;
         // Tauri TabBar new-session: shell sessions + recent by last_used.
         let mut shell: Vec<_> = self
             .connections
@@ -478,7 +480,7 @@ impl NyaTermApp {
         &mut self,
         cx: &mut Context<Self>,
     ) -> impl IntoElement {
-        let path = self.new_session_group_menu_path.clone();
+        let path = self.shell.chrome.new_session_group_menu_path.clone();
         let visible_group_ids =
             new_session_visible_group_ids(&self.connections, &self.connection_groups);
         let mut parent_group_id = None;
@@ -715,23 +717,26 @@ impl NyaTermApp {
     }
 
     fn open_new_session_all_sessions_menu(&mut self, cx: &mut Context<Self>) {
-        if !self.new_session_all_sessions_open {
-            self.new_session_all_sessions_open = true;
-            self.new_session_group_menu_path.clear();
+        if !self.shell.chrome.new_session_all_sessions_open {
+            self.shell.chrome.new_session_all_sessions_open = true;
+            self.shell.chrome.new_session_group_menu_path.clear();
             cx.notify();
         }
     }
 
     fn toggle_new_session_all_sessions_menu(&mut self, cx: &mut Context<Self>) {
-        self.new_session_all_sessions_open = !self.new_session_all_sessions_open;
-        self.new_session_group_menu_path.clear();
+        self.shell.chrome.new_session_all_sessions_open =
+            !self.shell.chrome.new_session_all_sessions_open;
+        self.shell.chrome.new_session_group_menu_path.clear();
         cx.notify();
     }
 
     fn close_new_session_all_sessions_menu(&mut self, cx: &mut Context<Self>) {
-        if self.new_session_all_sessions_open || !self.new_session_group_menu_path.is_empty() {
-            self.new_session_all_sessions_open = false;
-            self.new_session_group_menu_path.clear();
+        if self.shell.chrome.new_session_all_sessions_open
+            || !self.shell.chrome.new_session_group_menu_path.is_empty()
+        {
+            self.shell.chrome.new_session_all_sessions_open = false;
+            self.shell.chrome.new_session_group_menu_path.clear();
             cx.notify();
         }
     }
@@ -742,21 +747,27 @@ impl NyaTermApp {
         depth: usize,
         cx: &mut Context<Self>,
     ) {
-        let unchanged = self.new_session_all_sessions_open
-            && self.new_session_group_menu_path.get(depth) == Some(&group_id)
-            && self.new_session_group_menu_path.len() == depth + 1;
+        let unchanged = self.shell.chrome.new_session_all_sessions_open
+            && self.shell.chrome.new_session_group_menu_path.get(depth) == Some(&group_id)
+            && self.shell.chrome.new_session_group_menu_path.len() == depth + 1;
         if unchanged {
             return;
         }
-        self.new_session_all_sessions_open = true;
-        self.new_session_group_menu_path.truncate(depth);
-        self.new_session_group_menu_path.push(group_id);
+        self.shell.chrome.new_session_all_sessions_open = true;
+        self.shell
+            .chrome
+            .new_session_group_menu_path
+            .truncate(depth);
+        self.shell.chrome.new_session_group_menu_path.push(group_id);
         cx.notify();
     }
 
     fn truncate_new_session_group_menu(&mut self, depth: usize, cx: &mut Context<Self>) {
-        if self.new_session_group_menu_path.len() > depth {
-            self.new_session_group_menu_path.truncate(depth);
+        if self.shell.chrome.new_session_group_menu_path.len() > depth {
+            self.shell
+                .chrome
+                .new_session_group_menu_path
+                .truncate(depth);
             cx.notify();
         }
     }

crates/nyaterm-desktop/src/features/layout/workspace/surface/tabs.rs

@@ -368,7 +368,7 @@ impl NyaTermApp {
                 .then_with(|| left.2.cmp(&right.2))
                 .then_with(|| left.3.cmp(&right.3))
         });
-        if self.session_tab_scroll_into_view_pending {
+        if self.shell.chrome.session_tab_scroll_into_view_pending {
             if let Some(active_id) = self.session.active_id.as_deref() {
                 if let Some(index) = sessions.iter().position(|session| session.id == active_id) {
                     let pending_count = transient_tabs
@@ -376,10 +376,13 @@ impl NyaTermApp {
                         .filter(|(pending_index, _, _, _, _, _)| *pending_index <= index)
                         .count();
                     let child_index = index + pending_count;
-                    self.session_tab_strip_scroll.scroll_to_item(child_index);
+                    self.shell
+                        .chrome
+                        .session_tab_strip_scroll
+                        .scroll_to_item(child_index);
                 }
             }
-            self.session_tab_scroll_into_view_pending = false;
+            self.shell.chrome.session_tab_scroll_into_view_pending = false;
         }
         let mut tabs = div()
             .id("session-tab-strip-scroll")
@@ -391,7 +394,7 @@ impl NyaTermApp {
             // Tauri tab-strip-scroll: horizontal overflow instead of clipping tabs.
             .overflow_x_scroll()
             .overflow_y_hidden()
-            .track_scroll(&self.session_tab_strip_scroll);
+            .track_scroll(&self.shell.chrome.session_tab_strip_scroll);
 
         let mut transient_cursor = 0usize;
         for (tab_index, session) in sessions.into_iter().enumerate() {
@@ -436,7 +439,9 @@ impl NyaTermApp {
                 .as_deref()
                 .is_some_and(|id| self.tab_root_for_session(id) == session.id);
             let leaf_ids = self
-                .session_pane_roots
+                .shell
+                .workspace
+                .pane_roots
                 .get(&session.id)
                 .map(|root| root.session_ids())
                 .unwrap_or_else(|| vec![session.id.clone()]);
@@ -695,11 +700,17 @@ impl NyaTermApp {
         }
 
         // Tauri TabBar trailing chrome: optional open-tabs overflow menu + new session menu.
-        let open_tabs_menu = self.open_tabs_menu_open;
-        let new_session_menu = self.new_session_menu_open;
+        let open_tabs_menu = self.shell.chrome.open_tabs_menu_open;
+        let new_session_menu = self.shell.chrome.new_session_menu_open;
         let open_tabs_label = self.tr("terminal.openTabs").to_string();
         let new_session_label = self.tr("terminal.newSession").to_string();
-        let tab_strip_has_overflow = self.session_tab_strip_scroll.max_offset().width > px(0.);
+        let tab_strip_has_overflow = self
+            .shell
+            .chrome
+            .session_tab_strip_scroll
+            .max_offset()
+            .width
+            > px(0.);
         // Tauri shows Open Tabs only when the strip actually overflows.
         let show_open_tabs_menu = tab_strip_has_overflow || open_tabs_menu;
 

crates/nyaterm-desktop/src/features/mod.rs

@@ -87,7 +87,7 @@ pub(in crate::features) use session::{
 pub(in crate::features) use settings::{SecurityFeatureFocus, SecurityFeatureState};
 pub(in crate::features) use shell::{
     ChromeTooltip, SessionTabDragPayload, SessionTabDragPreview, SessionTabTooltip,
-    ShellFeatureState, TAB_MOUSE_ACTIONS, TabMouseActionTarget,
+    ShellFeatureInit, ShellFeatureState, TAB_MOUSE_ACTIONS, TabMouseActionTarget,
 };
 pub(in crate::features) use shell::{
     appearance_font_options, appearance_font_stack, gpui_code_font_family,

crates/nyaterm-desktop/src/features/pages/connections/menus.rs

@@ -59,7 +59,7 @@ impl NyaTermApp {
         cx: &mut Context<Self>,
     ) -> AnyElement {
         let palette = self.theme_palette();
-        let (viewport_width, viewport_height) = self.last_viewport_size;
+        let (viewport_width, viewport_height) = self.shell.viewport.size;
         let max_height = connection_menu_max_height(viewport_height);
         let submenu_offset = connection_submenu_offset(f32::from(x), viewport_width);
         deferred(
@@ -130,7 +130,7 @@ impl NyaTermApp {
         cx: &mut Context<Self>,
     ) -> AnyElement {
         let palette = self.theme_palette();
-        let max_height = connection_menu_max_height(self.last_viewport_size.1);
+        let max_height = connection_menu_max_height(self.shell.viewport.size.1);
         let ungrouped_ids = move_ids.clone();
         let mut panel = div()
             .id(SharedString::from(id))

crates/nyaterm-desktop/src/features/pages/remote/docker_view.rs

@@ -290,7 +290,7 @@ impl NyaTermApp {
                     self.tr("dockerManager.compose").to_string(),
                 ],
                 self.tr("common.more").to_string(),
-                self.right_panel_width,
+                self.shell.panels.right_width,
                 self.remote_ops.docker.tab_menu_open,
                 cx,
             ))

crates/nyaterm-desktop/src/features/pages/remote/process_view.rs

@@ -99,7 +99,7 @@ impl NyaTermApp {
             .cloned()
             .collect::<Vec<_>>();
         // Responsive mode first so hidden columns do not keep invalid sort keys.
-        let mode = process_display_mode(self.right_panel_width);
+        let mode = process_display_mode(self.shell.panels.right_width);
         if mode != ProcessDisplayMode::Wide
             && self.remote_ops.process.sort_key == RemoteProcessSortKey::User
         {

crates/nyaterm-desktop/src/features/pages/settings/mod.rs

@@ -21,7 +21,7 @@ impl NyaTermApp {
         &mut self,
         cx: &mut Context<Self>,
     ) -> impl IntoElement {
-        self.settings_surface(self.last_viewport_size.0, false, cx)
+        self.settings_surface(self.shell.viewport.size.0, false, cx)
     }
 
     pub(in crate::features) fn settings_window_view(
@@ -61,8 +61,8 @@ impl NyaTermApp {
         // Tauri SettingsPage shell: compact header + narrow nav + scroll content.
         let palette = self.theme_palette();
         let settings_title = self.tr("settings.title");
-        let active_group = self.tr(self.settings_active_tab.group_i18n_key());
-        let active_label = self.tr(self.settings_active_tab.i18n_key());
+        let active_group = self.tr(self.shell.navigation.settings.active_tab.group_i18n_key());
+        let active_label = self.tr(self.shell.navigation.settings.active_tab.i18n_key());
         let back_label = self.tr("common.close");
         div()
             .flex()
@@ -303,9 +303,24 @@ impl NyaTermApp {
         } else {
             224.
         };
-        let workspace_expanded = self.settings_expanded_groups.contains("workspace");
-        let terminal_expanded = self.settings_expanded_groups.contains("terminal_session");
-        let ai_expanded = self.settings_expanded_groups.contains("ai_group");
+        let workspace_expanded = self
+            .shell
+            .navigation
+            .settings
+            .expanded_groups
+            .contains("workspace");
+        let terminal_expanded = self
+            .shell
+            .navigation
+            .settings
+            .expanded_groups
+            .contains("terminal_session");
+        let ai_expanded = self
+            .shell
+            .navigation
+            .settings
+            .expanded_groups
+            .contains("ai_group");
 
         let mut sidebar_nav = div()
             .id(SharedString::from("settings-sidebar-scroll"))
@@ -540,8 +555,14 @@ impl NyaTermApp {
                 this.tooltip(move |_, cx| cx.new(|_| ChromeTooltip::new(title)).into())
             })
             .on_click(cx.listener(move |this, _, _, cx| {
-                if !this.settings_expanded_groups.insert(group.to_string()) {
-                    this.settings_expanded_groups.remove(group);
+                if !this
+                    .shell
+                    .navigation
+                    .settings
+                    .expanded_groups
+                    .insert(group.to_string())
+                {
+                    this.shell.navigation.settings.expanded_groups.remove(group);
                 }
                 cx.notify();
             }))
@@ -556,7 +577,7 @@ impl NyaTermApp {
         cx: &mut Context<Self>,
     ) -> impl IntoElement {
         let palette = self.theme_palette();
-        let selected = self.settings_active_tab == tab;
+        let selected = self.shell.navigation.settings.active_tab == tab;
         let label = self.tr(tab.i18n_key());
 
         // Tauri settings nav item: soft primary fill, no permanent green border.
@@ -619,7 +640,7 @@ impl NyaTermApp {
                 this.tooltip(move |_, cx| cx.new(|_| ChromeTooltip::new(label)).into())
             })
             .on_click(cx.listener(move |this, _, _, cx| {
-                this.settings_active_tab = tab;
+                this.shell.navigation.settings.active_tab = tab;
                 this.settings_state.appearance.menu_open = None;
                 cx.notify();
             }))
@@ -631,7 +652,7 @@ impl NyaTermApp {
         cx: &mut Context<Self>,
     ) -> impl IntoElement {
         let palette = self.theme_palette();
-        let active_tab = self.settings_active_tab;
+        let active_tab = self.shell.navigation.settings.active_tab;
         let active_label = self.tr(active_tab.i18n_key());
         let content = self.settings_tab_content(active_tab, cx);
         let compact = viewport_width < 640.;

crates/nyaterm-desktop/src/features/pages/settings/sync_backup/cloud_sync/mod.rs

@@ -436,7 +436,8 @@ impl NyaTermApp {
                                     "cloud-open-security",
                                     self.tr("settings.openSecuritySettings"),
                                     cx.listener(|this, _, _, cx| {
-                                        this.settings_active_tab = SettingsTab::Security;
+                                        this.shell.navigation.settings.active_tab =
+                                            SettingsTab::Security;
                                         cx.notify();
                                     }),
                                 )),

crates/nyaterm-desktop/src/features/pages/settings/workspace/appearance.rs

@@ -57,7 +57,7 @@ impl NyaTermApp {
                         settings_switch(
                             palette,
                             "appearance-panel-multi-open",
-                            self.panel_multi_open,
+                            self.shell.panels.multi_open,
                             cx.listener(|this, _, _, cx| {
                                 this.toggle_panel_multi_open(cx);
                             }),

crates/nyaterm-desktop/src/features/pages/transfers/browser/view.rs

@@ -287,7 +287,7 @@ impl NyaTermApp {
         } else {
             // Tauri File Explorer virtual list (30px rows and overscan).
             let viewport_rows = transfer_browser_viewport_rows(
-                self.last_viewport_size.1,
+                self.shell.viewport.size.1,
                 self.transfer.panel.height,
                 self.transfer.browser.viewport_height,
             );
@@ -527,7 +527,7 @@ impl NyaTermApp {
                         let parent_count = usize::from(current_path != "/" && current_path != ".");
                         let total = this.visible_transfer_browser_entries().len() + parent_count;
                         let viewport_rows = transfer_browser_viewport_rows(
-                            this.last_viewport_size.1,
+                            this.shell.viewport.size.1,
                             this.transfer.panel.height,
                             this.transfer.browser.viewport_height,
                         );

crates/nyaterm-desktop/src/features/pages/transfers/overlays.rs

@@ -32,7 +32,7 @@ impl NyaTermApp {
         let description = self
             .tr("fileTransfer.deleteConfirmDesc")
             .replace("{{name}}", &state.title);
-        let dialog_width = transfer_dialog_width(self.last_viewport_size.0, 320.);
+        let dialog_width = transfer_dialog_width(self.shell.viewport.size.0, 320.);
 
         div()
             .id(SharedString::from("transfer-job-delete-overlay"))
@@ -152,7 +152,7 @@ impl NyaTermApp {
         let retry_id = state.job_id.clone();
         let open_id = state.job_id.clone();
         let delete_id = state.job_id.clone();
-        let (viewport_w, viewport_h) = self.last_viewport_size;
+        let (viewport_w, viewport_h) = self.shell.viewport.size;
         let (menu_x, menu_y, menu_max_height) = transfer_menu_position(
             f32::from(state.x),
             f32::from(state.y),

crates/nyaterm-desktop/src/features/pages/transfers/overlays_context.rs

@@ -46,7 +46,7 @@ impl NyaTermApp {
             .map(|entry| self.enabled_transfer_file_ai_actions_for_entry(entry))
             .unwrap_or_default();
         let has_ai_actions = !selected_file_ai_actions.is_empty();
-        let (viewport_w, viewport_h) = self.last_viewport_size;
+        let (viewport_w, viewport_h) = self.shell.viewport.size;
         let preferred_height = if state.is_current_directory {
             380.
         } else if state.is_parent {

crates/nyaterm-desktop/src/features/pages/transfers/overlays_create.rs

@@ -23,7 +23,7 @@ impl NyaTermApp {
         cx: &mut Context<Self>,
     ) -> impl IntoElement {
         let palette = self.theme_palette();
-        let dialog_width = transfer_dialog_width(self.last_viewport_size.0, 500.);
+        let dialog_width = transfer_dialog_width(self.shell.viewport.size.0, 500.);
         let state = self
             .transfer
             .file_ops
@@ -228,7 +228,7 @@ impl NyaTermApp {
         cx: &mut Context<Self>,
     ) -> impl IntoElement {
         let palette = self.theme_palette();
-        let dialog_width = transfer_dialog_width(self.last_viewport_size.0, 500.);
+        let dialog_width = transfer_dialog_width(self.shell.viewport.size.0, 500.);
         let state = self
             .transfer
             .file_ops
@@ -431,7 +431,7 @@ impl NyaTermApp {
         cx: &mut Context<Self>,
     ) -> impl IntoElement {
         let palette = self.theme_palette();
-        let dialog_width = transfer_dialog_width(self.last_viewport_size.0, 480.);
+        let dialog_width = transfer_dialog_width(self.shell.viewport.size.0, 480.);
         let state = self
             .transfer
             .file_ops

crates/nyaterm-desktop/src/features/pages/transfers/overlays_delete_move.rs

@@ -42,7 +42,7 @@ impl NyaTermApp {
             .map(|path| remote_file_name(path))
             .collect::<Vec<_>>();
         let remaining_items = delete_count.saturating_sub(preview_items.len());
-        let dialog_width = transfer_dialog_width(self.last_viewport_size.0, 320.);
+        let dialog_width = transfer_dialog_width(self.shell.viewport.size.0, 320.);
 
         div()
             .id(SharedString::from("transfer-delete-overlay"))
@@ -170,7 +170,7 @@ impl NyaTermApp {
                 cx,
             )
             .into_any_element();
-        let dialog_width = transfer_dialog_width(self.last_viewport_size.0, 384.);
+        let dialog_width = transfer_dialog_width(self.shell.viewport.size.0, 384.);
 
         div()
             .id(SharedString::from("transfer-move-overlay"))

crates/nyaterm-desktop/src/features/pages/transfers/overlays_editor.rs

@@ -365,7 +365,7 @@ impl NyaTermApp {
             .min_w_0()
             .flex()
             .overflow_x_scroll();
-        let tabs_menu_max_height = (self.last_viewport_size.1 - 48.).clamp(160., 360.);
+        let tabs_menu_max_height = (self.shell.viewport.size.1 - 48.).clamp(160., 360.);
         let tabs_menu_bg = if standalone {
             rgb(palette.surface)
         } else {

crates/nyaterm-desktop/src/features/pages/transfers/overlays_favorites.rs

@@ -57,7 +57,7 @@ impl NyaTermApp {
             .iter()
             .cloned()
             .collect::<Vec<_>>();
-        let (viewport_w, viewport_h) = self.last_viewport_size;
+        let (viewport_w, viewport_h) = self.shell.viewport.size;
         let (menu_x, menu_y, menu_max_height) = transfer_menu_position(
             f32::from(state.x),
             f32::from(state.y),

crates/nyaterm-desktop/src/features/pages/transfers/overlays_properties.rs

@@ -80,8 +80,8 @@ impl NyaTermApp {
         let property_mode = parse_transfer_mode(&state.mode_value)
             .or(entry.permissions)
             .unwrap_or(0o644);
-        let dialog_width = (self.last_viewport_size.0 - 32.).min(460.).max(280.);
-        let dialog_max_height = (self.last_viewport_size.1 * 0.75).clamp(320., 720.);
+        let dialog_width = (self.shell.viewport.size.0 - 32.).min(460.).max(280.);
+        let dialog_max_height = (self.shell.viewport.size.1 * 0.75).clamp(320., 720.);
         let owner_input = self
             .text_input_box(
                 "transfer.properties.owner",

crates/nyaterm-desktop/src/features/pages/transfers/overlays_unknown.rs

@@ -38,7 +38,7 @@ impl NyaTermApp {
         } else {
             state.entry.name.clone()
         };
-        let dialog_width = transfer_dialog_width(self.last_viewport_size.0, 512.);
+        let dialog_width = transfer_dialog_width(self.shell.viewport.size.0, 512.);
         let description = self
             .tr("fileExplorer.unknownFileTypeDesc")
             .replace("{{name}}", &name);

crates/nyaterm-desktop/src/features/pages/transfers/overlays_upload.rs

@@ -48,7 +48,7 @@ impl NyaTermApp {
                 x: px(24.),
                 y: px(24.),
             });
-        let (viewport_w, viewport_h) = self.last_viewport_size;
+        let (viewport_w, viewport_h) = self.shell.viewport.size;
         let (menu_x, menu_y, menu_max_height) = transfer_menu_position(
             f32::from(state.x),
             f32::from(state.y),

crates/nyaterm-desktop/src/features/pages/transfers/path_bar.rs

@@ -316,7 +316,7 @@ impl NyaTermApp {
                 TransferBrowserChildrenMenuStatus::Error(_) => 112.,
             },
         };
-        let (viewport_w, viewport_h) = self.last_viewport_size;
+        let (viewport_w, viewport_h) = self.shell.viewport.size;
         let (menu_x, menu_y, menu_max_height) = transfer_menu_position(
             f32::from(menu.x),
             f32::from(menu.y),

crates/nyaterm-desktop/src/features/pages/workspace/mod.rs

@@ -17,8 +17,8 @@ impl NyaTermApp {
         // register/close/idle already keep terminal_windows coherent.
         let multi_leaf = self.terminal_windows_is_multi_leaf();
         let has_connect_failure = self.has_failed_session_start()
-            || (self.last_connect_failure_name.is_some()
-                && self.last_connect_failure_error.is_some());
+            || (self.shell.chrome.last_connect_failure_name.is_some()
+                && self.shell.chrome.last_connect_failure_error.is_some());
         let show_tab_strip = !multi_leaf
             && (self.ordered_tab_session_count() > 0
                 || self.has_pending_session_start()
@@ -52,8 +52,8 @@ impl NyaTermApp {
                 return self.pending_workspace_state().into_any_element();
             }
             if self.has_failed_session_start()
-                || (self.last_connect_failure_name.is_some()
-                    && self.last_connect_failure_error.is_some())
+                || (self.shell.chrome.last_connect_failure_name.is_some()
+                    && self.shell.chrome.last_connect_failure_error.is_some())
             {
                 return self.failed_workspace_state().into_any_element();
             }
@@ -72,10 +72,10 @@ impl NyaTermApp {
                     .into_any_element();
             }
         }
-        let root = self
-            .workspace_split
-            .clone()
-            .unwrap_or_else(|| WorkspacePaneNode::leaf(self.session.active_id.clone().unwrap()));
+        let root =
+            self.shell.workspace.split.clone().unwrap_or_else(|| {
+                WorkspacePaneNode::leaf(self.session.active_id.clone().unwrap())
+            });
 
         let show_chrome = root.is_split();
         div()

crates/nyaterm-desktop/src/features/pages/workspace/terminal_windows.rs

@@ -77,7 +77,9 @@ impl NyaTermApp {
                         .unwrap_or(("Session", "icons/conn/terminal.svg"));
                     let custom_color = self.session.tab_colors.get(tab_id).copied();
                     let leaf_ids = self
-                        .session_pane_roots
+                        .shell
+                        .workspace
+                        .pane_roots
                         .get(tab_id)
                         .map(|root| root.session_ids())
                         .unwrap_or_else(|| vec![tab_id.clone()]);
@@ -327,7 +329,8 @@ impl NyaTermApp {
                         .on_click(cx.listener({
                             let leaf_id = id.clone();
                             move |this, _, window, cx| {
-                                this.focused_terminal_window_leaf_id = Some(leaf_id.clone());
+                                this.shell.workspace.focused_terminal_leaf_id =
+                                    Some(leaf_id.clone());
                                 this.start_local_session(window, cx);
                             }
                         })),
@@ -396,7 +399,8 @@ impl NyaTermApp {
                         cx.listener({
                             let leaf_id = id.clone();
                             move |this, _, _, cx| {
-                                this.focused_terminal_window_leaf_id = Some(leaf_id.clone());
+                                this.shell.workspace.focused_terminal_leaf_id =
+                                    Some(leaf_id.clone());
                                 cx.notify();
                             }
                         }),

crates/nyaterm-desktop/src/features/panels/active_session_menu_overlay.rs

@@ -29,7 +29,7 @@ impl NyaTermApp {
         } else {
             self.tr("tabCtx.disconnect").to_string()
         };
-        let (viewport_w, viewport_h) = self.last_viewport_size;
+        let (viewport_w, viewport_h) = self.shell.viewport.size;
         let (menu_x, menu_y) = active_session_clamped_menu_position(
             f32::from(menu.x) - 132.,
             f32::from(menu.y) + 8.,

crates/nyaterm-desktop/src/features/panels/connection_import_overlay.rs

@@ -13,8 +13,8 @@ impl NyaTermApp {
         cx: &mut Context<Self>,
     ) -> impl IntoElement {
         let palette = self.theme_palette();
-        let narrow = self.last_viewport_size.0 < 520.;
-        let width = (self.last_viewport_size.0 - 32.).clamp(280., 480.);
+        let narrow = self.shell.viewport.size.0 < 520.;
+        let width = (self.shell.viewport.size.0 - 32.).clamp(280., 480.);
         let docs_url = if self
             .settings
             .language

crates/nyaterm-desktop/src/features/panels/multi_line_paste_overlay.rs

@@ -14,7 +14,7 @@ impl NyaTermApp {
         cx: &mut Context<Self>,
     ) -> impl IntoElement {
         let palette = self.theme_palette();
-        let (viewport_w, viewport_h) = self.last_viewport_size;
+        let (viewport_w, viewport_h) = self.shell.viewport.size;
         let draft = self
             .terminal
             .paste

crates/nyaterm-desktop/src/features/panels/quick_command_category_menu_overlay.rs

@@ -14,7 +14,7 @@ impl NyaTermApp {
         let category_id = menu.category_id.clone();
         let rename_id = category_id.clone();
         let delete_id = category_id.clone();
-        let (viewport_w, viewport_h) = self.last_viewport_size;
+        let (viewport_w, viewport_h) = self.shell.viewport.size;
         let (menu_x, menu_y) = quick_command_category_clamped_menu_position(
             f32::from(menu.x),
             f32::from(menu.y),

crates/nyaterm-desktop/src/features/panels/quick_command_category_overlays.rs

@@ -38,7 +38,7 @@ impl NyaTermApp {
             .child(
                 div()
                     .id(SharedString::from("quick-command-category-delete-dialog"))
-                    .w(px((self.last_viewport_size.0 - 32.).clamp(280., 384.)))
+                    .w(px((self.shell.viewport.size.0 - 32.).clamp(280., 384.)))
                     .rounded_md()
                     .border_1()
                     .border_color(rgb(0x7f1d1d))
@@ -136,7 +136,7 @@ impl NyaTermApp {
             .child(
                 div()
                     .id(SharedString::from("quick-command-category-rename-dialog"))
-                    .w(px((self.last_viewport_size.0 - 32.).clamp(280., 384.)))
+                    .w(px((self.shell.viewport.size.0 - 32.).clamp(280., 384.)))
                     .rounded_md()
                     .border_1()
                     .border_color(rgb(palette.border))

crates/nyaterm-desktop/src/features/panels/quick_command_delete_overlay.rs

@@ -35,7 +35,7 @@ impl NyaTermApp {
             .child(
                 div()
                     .id(SharedString::from("quick-command-delete-dialog"))
-                    .w(px((self.last_viewport_size.0 - 32.).clamp(280., 384.)))
+                    .w(px((self.shell.viewport.size.0 - 32.).clamp(280., 384.)))
                     .rounded_md()
                     .border_1()
                     .border_color(rgb(0x7f1d1d))

crates/nyaterm-desktop/src/features/panels/quick_command_details_overlay.rs

@@ -30,7 +30,7 @@ impl NyaTermApp {
             .filter(|description| !description.is_empty());
         let command_text = command.command.clone();
         let estimated_h = if description.is_some() { 224. } else { 182. };
-        let (viewport_w, viewport_h) = self.last_viewport_size;
+        let (viewport_w, viewport_h) = self.shell.viewport.size;
         let (popover_x, popover_y) = quick_command_details_popover_position(
             f32::from(anchor_x) - 304.,
             f32::from(anchor_y) - estimated_h - 6.,

crates/nyaterm-desktop/src/features/panels/quick_command_editor_overlay.rs

@@ -17,7 +17,7 @@ impl NyaTermApp {
         &mut self,
         cx: &mut Context<Self>,
     ) -> AnyElement {
-        self.quick_command_editor_surface(self.last_viewport_size.0, false, cx)
+        self.quick_command_editor_surface(self.shell.viewport.size.0, false, cx)
     }
 
     pub(in crate::features) fn quick_command_editor_window_view(

crates/nyaterm-desktop/src/features/panels/quick_command_import_overlay.rs

@@ -48,7 +48,7 @@ impl NyaTermApp {
             .child(
                 div()
                     .id(SharedString::from("quick-command-import-dialog"))
-                    .w(px((self.last_viewport_size.0 - 32.).clamp(280., 380.)))
+                    .w(px((self.shell.viewport.size.0 - 32.).clamp(280., 380.)))
                     .max_w_full()
                     .rounded_md()
                     .border_1()

crates/nyaterm-desktop/src/features/panels/quick_command_row_menu_overlay.rs

@@ -16,7 +16,7 @@ impl NyaTermApp {
         let all_command_id = command_id.clone();
         let delete_command_id = command_id.clone();
         let can_send_to_all = self.live_session_count() > 1;
-        let (viewport_w, viewport_h) = self.last_viewport_size;
+        let (viewport_w, viewport_h) = self.shell.viewport.size;
         let (menu_x, menu_y) = quick_command_clamped_menu_position(
             f32::from(menu.x),
             f32::from(menu.y),

crates/nyaterm-desktop/src/features/panels/quick_command_variable_overlay.rs

@@ -147,7 +147,7 @@ impl NyaTermApp {
             .child(
                 div()
                     .id(SharedString::from("quick-command-variable-dialog"))
-                    .w(px((self.last_viewport_size.0 - 32.).clamp(280., 400.)))
+                    .w(px((self.shell.viewport.size.0 - 32.).clamp(280., 400.)))
                     .max_w_full()
                     .rounded_md()
                     .border_1()
@@ -173,7 +173,7 @@ impl NyaTermApp {
                         div()
                             .id("quick-command-variable-body")
                             .p_5()
-                            .max_h(px((self.last_viewport_size.1 * 0.6).clamp(180., 420.)))
+                            .max_h(px((self.shell.viewport.size.1 * 0.6).clamp(180., 420.)))
                             .overflow_y_scroll()
                             .child(rows)
                             .child(

crates/nyaterm-desktop/src/features/panels/quick_commands_panel/panel/mod.rs

@@ -63,11 +63,11 @@ impl NyaTermApp {
         let category_sidebar = self.quick_command_category_sidebar(categories, palette, cx);
         let view_mode = self.quick_command_state.list.view_mode;
         let tile_columns = quick_command_tile_column_count(
-            self.last_viewport_size.0,
-            self.left_panel_width,
-            self.right_panel_width,
-            !self.left_sidebar_collapsed,
-            !self.right_inspector_collapsed,
+            self.shell.viewport.size.0,
+            self.shell.panels.left_width,
+            self.shell.panels.right_width,
+            !self.shell.panels.left_collapsed,
+            !self.shell.panels.right_collapsed,
         );
         let logical_row_height = match view_mode {
             QuickCommandViewMode::Tile => 32.,

crates/nyaterm-desktop/src/features/panels/quick_switch_overlay.rs

@@ -14,7 +14,7 @@ impl NyaTermApp {
         cx: &mut Context<Self>,
     ) -> impl IntoElement {
         let palette = self.theme_palette();
-        let (viewport_w, viewport_h) = self.last_viewport_size;
+        let (viewport_w, viewport_h) = self.shell.viewport.size;
         let items = self.filtered_quick_switch_items(cx);
         self.update_quick_switch_state(cx, |store| {
             store.clamp_quick_switch_selected_index(items.len())
@@ -28,7 +28,7 @@ impl NyaTermApp {
             cx,
         );
         let query_focus = query_input.read(cx).focus_handle();
-        let list_max_height = (self.last_viewport_size.1 * 0.55).clamp(160., 384.);
+        let list_max_height = (self.shell.viewport.size.1 * 0.55).clamp(160., 384.);
         let selected_row_bg = rgba((palette.primary << 8) | 0x26);
         let hover_row_bg = self.shell_surface_color(palette.hover);
         let mut rows = div()

crates/nyaterm-desktop/src/features/panels/session_confirm_overlays.rs

@@ -54,7 +54,7 @@ impl NyaTermApp {
             .child(
                 div()
                     .id("close-all-sessions-confirm-dialog")
-                    .w(px((self.last_viewport_size.0 - 32.).clamp(280., 400.)))
+                    .w(px((self.shell.viewport.size.0 - 32.).clamp(280., 400.)))
                     .max_w_full()
                     .mx_4()
                     .rounded_md()

crates/nyaterm-desktop/src/features/panels/session_overlays.rs

@@ -23,7 +23,7 @@ impl NyaTermApp {
             )
             .into_any_element();
         let can_save = !self.session.dialogs.rename_draft.trim().is_empty();
-        let dialog_width = (self.last_viewport_size.0 - 32.).clamp(280., 320.);
+        let dialog_width = (self.shell.viewport.size.0 - 32.).clamp(280., 320.);
 
         div()
             .id(SharedString::from("rename-tab-overlay"))
@@ -350,7 +350,7 @@ impl NyaTermApp {
             .into_any_element();
         let can_submit = !self.session.dialogs.startup_command_draft.trim().is_empty();
         let delay_label = format!("{} ms", self.session.dialogs.startup_command_delay_ms);
-        let dialog_width = (self.last_viewport_size.0 - 32.).clamp(280., 448.);
+        let dialog_width = (self.shell.viewport.size.0 - 32.).clamp(280., 448.);
 
         div()
             .id(SharedString::from("startup-command-overlay"))

crates/nyaterm-desktop/src/features/panels/sync_groups_overlay.rs

@@ -17,7 +17,7 @@ impl NyaTermApp {
         cx: &mut Context<Self>,
     ) -> impl IntoElement {
         let palette = self.theme_palette();
-        let (viewport_w, viewport_h) = self.last_viewport_size;
+        let (viewport_w, viewport_h) = self.shell.viewport.size;
         let dialog_width = (viewport_w - 24.).clamp(280., 900.);
         let dialog_height = (viewport_h - 56.).clamp(280., 500.);
         let groups_width = (dialog_width * 0.23).clamp(160., 208.);

crates/nyaterm-desktop/src/features/panels/tab_actions_overlay/compact.rs

@@ -33,7 +33,7 @@ impl NyaTermApp {
         _session_count: usize,
         cx: &mut Context<Self>,
     ) -> gpui::AnyElement {
-        let (viewport_w, viewport_h) = self.last_viewport_size;
+        let (viewport_w, viewport_h) = self.shell.viewport.size;
         let menu_max_height = (viewport_h - 16.).clamp(160., 440.);
         let (menu_x, menu_y) = if let Some((x, y)) = self.session.dialogs.tab_actions_anchor {
             clamp_tab_actions_position(x, y, 240., menu_max_height, viewport_w, viewport_h)

crates/nyaterm-desktop/src/features/panels/tab_actions_overlay/overlay.rs

@@ -69,9 +69,9 @@ impl NyaTermApp {
             .active_id
             .as_deref()
             .map(|id| self.tab_root_for_session(id))
-            .and_then(|root| self.session_pane_roots.get(&root))
+            .and_then(|root| self.shell.workspace.pane_roots.get(&root))
             .is_some_and(|root| root.is_split())
-            || self.workspace_split.is_some();
+            || self.shell.workspace.split.is_some();
         let scroll_offset = self
             .terminal
             .view

crates/nyaterm-desktop/src/features/panels/temporary_ssh_link_overlay.rs

@@ -55,7 +55,7 @@ impl NyaTermApp {
             .child(
                 div()
                     .id(SharedString::from("temporary-ssh-link-dialog"))
-                    .w(px((self.last_viewport_size.0 - 32.).clamp(280., 480.)))
+                    .w(px((self.shell.viewport.size.0 - 32.).clamp(280., 480.)))
                     .max_w_full()
                     .mx_4()
                     .rounded_md()

crates/nyaterm-desktop/src/features/panels/terminal_actions_overlay.rs

@@ -14,7 +14,7 @@ impl NyaTermApp {
         cx: &mut Context<Self>,
     ) -> impl IntoElement {
         let palette = self.theme_palette();
-        let (viewport_w, viewport_h) = self.last_viewport_size;
+        let (viewport_w, viewport_h) = self.shell.viewport.size;
         let visible_text = self.active_terminal_visible_text();
         let buffer_tail = self.active_terminal_buffer_tail();
         let visible_lines = visible_text.lines().count();
@@ -347,7 +347,7 @@ impl NyaTermApp {
                                 self.tr("terminalActions.sessionLog"),
                                 cx.listener(|this, _, _, cx| {
                                     this.terminal.menus.actions_open = false;
-                                    this.right_focus = RightFocus::Recording;
+                                    this.shell.panels.right_focus = RightFocus::Recording;
                                     cx.notify();
                                 }),
                             ))

crates/nyaterm-desktop/src/features/panels/update_overlay.rs

@@ -21,8 +21,8 @@ impl NyaTermApp {
         let available =
             !checking && !failed && update_info.as_ref().is_some_and(|info| info.available);
         let portable = self.runtime.mode() == RuntimeMode::Portable;
-        let (_, viewport_h) = self.last_viewport_size;
-        let dialog_width = (self.last_viewport_size.0 - 32.).clamp(320., 560.);
+        let (_, viewport_h) = self.shell.viewport.size;
+        let dialog_width = (self.shell.viewport.size.0 - 32.).clamp(320., 560.);
         let release_url = update_info
             .as_ref()
             .and_then(|info| info.html_url.clone())

crates/nyaterm-desktop/src/features/remote/remote_runtime/docker.rs

@@ -233,7 +233,7 @@ impl NyaTermApp {
         if !command.ends_with('\n') {
             command.push('\n');
         }
-        self.selected_nav = NavItem::Workspace;
+        self.shell.navigation.selected_nav = NavItem::Workspace;
         if self.send_terminal_input(command.into_bytes(), cx) {
             self.remote_ops.docker.status = status;
             self.terminal.view.status = self.remote_ops.docker.status.clone();

crates/nyaterm-desktop/src/features/root.rs

@@ -82,23 +82,23 @@ impl NyaTermApp {
             .on_mouse_down(
                 MouseButton::Left,
                 cx.listener(|this, _, _, cx| {
-                    let changed = this.title_menu_open.is_some()
-                        || this.header_status.menu_open
-                        || this.open_tabs_menu_open
-                        || this.new_session_menu_open
-                        || this.new_session_all_sessions_open
-                        || !this.new_session_group_menu_path.is_empty()
+                    let changed = this.shell.chrome.title_menu_open.is_some()
+                        || this.shell.chrome.header_status.menu_open
+                        || this.shell.chrome.open_tabs_menu_open
+                        || this.shell.chrome.new_session_menu_open
+                        || this.shell.chrome.new_session_all_sessions_open
+                        || !this.shell.chrome.new_session_group_menu_path.is_empty()
                         || this.remote_ops.docker.tab_menu_open
                         || this.remote_ops.docker.header_menu_open
                         || this.connection_state.list_more_menu_is_open();
                     if changed {
-                        this.title_menu_open = None;
-                        this.title_menu_submenu = None;
-                        this.header_status.menu_open = false;
-                        this.open_tabs_menu_open = false;
-                        this.new_session_menu_open = false;
-                        this.new_session_all_sessions_open = false;
-                        this.new_session_group_menu_path.clear();
+                        this.shell.chrome.title_menu_open = None;
+                        this.shell.chrome.title_menu_submenu = None;
+                        this.shell.chrome.header_status.menu_open = false;
+                        this.shell.chrome.open_tabs_menu_open = false;
+                        this.shell.chrome.new_session_menu_open = false;
+                        this.shell.chrome.new_session_all_sessions_open = false;
+                        this.shell.chrome.new_session_group_menu_path.clear();
                         this.remote_ops.docker.tab_menu_open = false;
                         this.remote_ops.docker.header_menu_open = false;
                         this.connection_state.close_list_more_menu();
@@ -205,7 +205,7 @@ impl NyaTermApp {
                 .into();
                 if let Some((tile_width, tile_height)) = wallpaper_tile_size {
                     let (columns, rows) =
-                        wallpaper_tile_grid(self.last_viewport_size, (tile_width, tile_height));
+                        wallpaper_tile_grid(self.shell.viewport.size, (tile_width, tile_height));
                     let mut layer = div()
                         .absolute()
                         .inset_0()
@@ -251,11 +251,12 @@ impl NyaTermApp {
     }
 
     fn wallpaper_tile_size(&mut self, path: &str) -> (f32, f32) {
-        if let Some((cached_path, width, height)) = self.wallpaper_tile_dimensions.as_ref()
+        if let Some((cached_path, width, height)) =
+            self.shell.viewport.wallpaper_tile_dimensions.as_ref()
             && cached_path == path
         {
             return fit_wallpaper_tile_size(
-                self.last_viewport_size,
+                self.shell.viewport.size,
                 (*width as f32, *height as f32),
             );
         }
@@ -263,8 +264,8 @@ impl NyaTermApp {
             .ok()
             .filter(|(width, height)| *width > 0 && *height > 0)
             .unwrap_or((256, 256));
-        self.wallpaper_tile_dimensions = Some((path.to_string(), width, height));
-        fit_wallpaper_tile_size(self.last_viewport_size, (width as f32, height as f32))
+        self.shell.viewport.wallpaper_tile_dimensions = Some((path.to_string(), width, height));
+        fit_wallpaper_tile_size(self.shell.viewport.size, (width as f32, height as f32))
     }
 
     fn workspace_surface(
@@ -273,7 +274,9 @@ impl NyaTermApp {
         window: &mut Window,
         cx: &mut Context<Self>,
     ) -> AnyElement {
-        if self.main_mode == MainMode::Page && self.selected_nav == NavItem::Settings {
+        if self.shell.navigation.main_mode == MainMode::Page
+            && self.shell.navigation.selected_nav == NavItem::Settings
+        {
             div()
                 .flex()
                 .flex_1()
@@ -285,15 +288,15 @@ impl NyaTermApp {
             let compact_layout = !cfg!(target_os = "macos");
             let has_left_activity_items = self.activity_side_has_items(ActivitySide::Left);
             let has_right_activity_items = self.activity_side_has_items(ActivitySide::Right);
-            let left_overlay_mode = compact_layout && self.last_viewport_size.0 < 1024.;
-            let right_overlay_mode = compact_layout && self.last_viewport_size.0 < 768.;
+            let left_overlay_mode = compact_layout && self.shell.viewport.size.0 < 1024.;
+            let right_overlay_mode = compact_layout && self.shell.viewport.size.0 < 768.;
             let left_drawer_open = has_left_activity_items
                 && left_overlay_mode
-                && self.mobile_left_open
+                && self.shell.panels.mobile_left_open
                 && self.left_side_open();
             let right_drawer_open = has_right_activity_items
                 && right_overlay_mode
-                && self.mobile_right_open
+                && self.shell.panels.mobile_right_open
                 && self.right_side_open();
             let mut surface = div()
                 .flex()
@@ -324,7 +327,7 @@ impl NyaTermApp {
                     this.child(self.activity_bar(ActivitySide::Right, cx))
                 });
 
-            if self.terminal_windows_is_multi_leaf() && self.new_session_menu_open {
+            if self.terminal_windows_is_multi_leaf() && self.shell.chrome.new_session_menu_open {
                 surface = surface.child(self.render_new_session_menu(cx));
             }
 
@@ -336,8 +339,8 @@ impl NyaTermApp {
                         .inset_0()
                         .bg(rgba(0x00000080))
                         .on_click(cx.listener(|this, _, _, cx| {
-                            this.mobile_left_open = false;
-                            this.mobile_right_open = false;
+                            this.shell.panels.mobile_left_open = false;
+                            this.shell.panels.mobile_right_open = false;
                             cx.notify();
                         })),
                 );
@@ -439,9 +442,9 @@ impl NyaTermApp {
                     )
                     .on_click(cx.listener(move |this, _, _, cx| {
                         if left {
-                            this.mobile_left_open = false;
+                            this.shell.panels.mobile_left_open = false;
                         } else {
-                            this.mobile_right_open = false;
+                            this.shell.panels.mobile_right_open = false;
                         }
                         cx.notify();
                     })),
@@ -633,9 +636,10 @@ impl NyaTermApp {
             .when(quick_switch_open, |this| {
                 this.child(self.quick_switch_overlay(cx))
             })
-            .when(self.activity_bar_context_menu.is_some(), |this| {
-                this.child(self.activity_bar_context_menu_overlay(cx))
-            })
+            .when(
+                self.shell.chrome.activity_bar_context_menu.is_some(),
+                |this| this.child(self.activity_bar_context_menu_overlay(cx)),
+            )
             .when(overlay.locked, |this| {
                 this.child(self.lock_screen_overlay(window, cx))
             })
@@ -657,8 +661,8 @@ impl NyaTermApp {
     }
 
     fn modal_child_window_open(&self) -> bool {
-        self.settings_window.is_some()
-            || self.settings_window_open_pending
+        self.shell.navigation.settings.window.is_some()
+            || self.shell.navigation.settings.window_open_pending
             || self.quick_command_state.editor.window.is_some()
             || self.quick_command_state.editor.window_open_pending
             || self.connection_state.editor_modal_window_open_or_pending()
@@ -667,9 +671,9 @@ impl NyaTermApp {
     }
 
     fn activate_modal_child_window(&mut self, cx: &mut Context<Self>) -> bool {
-        if self.settings_window.is_some() {
+        if self.shell.navigation.settings.window.is_some() {
             self.activate_settings_window(cx)
-        } else if self.settings_window_open_pending {
+        } else if self.shell.navigation.settings.window_open_pending {
             true
         } else if self.quick_command_state.editor.window.is_some() {
             self.activate_quick_command_window(cx)

crates/nyaterm-desktop/src/features/session/session_dialog_runtime.rs

@@ -214,9 +214,8 @@ impl NyaTermApp {
         self.clear_terminal_mouse_report_for_session(session_id);
         self.session.start.reconnect_failures.remove(session_id);
         self.session.order.retain(|id| id != session_id);
-        self.session_tab_owner.remove(session_id);
         // If this leaf was a tab root, drop its pane tree (prune will rekey survivors).
-        self.session_pane_roots.remove(session_id);
+        self.shell.workspace.remove_session(session_id);
         let multiplex_key = self
             .session
             .metadata

crates/nyaterm-desktop/src/features/session/session_lifecycle.rs

@@ -105,8 +105,8 @@ impl NyaTermApp {
                 );
             }
         }
-        self.selected_nav = NavItem::Workspace;
-        self.main_mode = MainMode::Workspace;
+        self.shell.navigation.selected_nav = NavItem::Workspace;
+        self.shell.navigation.main_mode = MainMode::Workspace;
         cx.notify();
     }
 
@@ -169,8 +169,8 @@ impl NyaTermApp {
             existing_multiplex,
             cx,
         );
-        self.selected_nav = NavItem::Workspace;
-        self.main_mode = MainMode::Workspace;
+        self.shell.navigation.selected_nav = NavItem::Workspace;
+        self.shell.navigation.main_mode = MainMode::Workspace;
         cx.notify();
     }
 
@@ -420,8 +420,8 @@ impl NyaTermApp {
         self.session
             .busy_actions
             .retain(|id, _| self.session.metadata.contains_key(id));
-        self.selected_nav = NavItem::Workspace;
-        self.main_mode = MainMode::Workspace;
+        self.shell.navigation.selected_nav = NavItem::Workspace;
+        self.shell.navigation.main_mode = MainMode::Workspace;
         cx.notify();
     }
 
@@ -463,17 +463,7 @@ impl NyaTermApp {
                 .insert(new_id.to_string(), history);
         }
 
-        let mut pane_roots = std::mem::take(&mut self.session_pane_roots);
-        for root in pane_roots.values_mut() {
-            root.replace_session_id(old_id, new_id);
-        }
-        if let Some(root) = pane_roots.remove(old_id) {
-            pane_roots.insert(new_id.to_string(), root);
-        }
-        self.session_pane_roots = pane_roots;
-        if let Some(root) = self.workspace_split.as_mut() {
-            root.replace_session_id(old_id, new_id);
-        }
+        self.shell.workspace.replace_session_id(old_id, new_id);
         if let Some(root) = self.terminal.windows.tree.as_mut() {
             root.replace_tab_id(old_id, new_id);
         }
@@ -481,7 +471,6 @@ impl NyaTermApp {
         if self.session.active_id.as_deref() == Some(old_id) {
             self.activate_session_id(new_id);
         }
-        self.rebuild_session_tab_owners();
         self.sync_workspace_split_from_active_tab();
     }
 }

crates/nyaterm-desktop/src/features/session/session_order.rs

@@ -128,7 +128,9 @@ impl NyaTermApp {
     /// True when this session is a secondary leaf inside another tab's pane tree
     /// (Tauri: multiple SessionPanes under one Tab, only one strip entry).
     pub(in crate::features) fn is_secondary_pane_session(&self, session_id: &str) -> bool {
-        self.session_tab_owner
+        self.shell
+            .workspace
+            .tab_owner
             .get(session_id)
             .is_some_and(|owner| owner != session_id)
     }
@@ -138,7 +140,7 @@ impl NyaTermApp {
         let mut current = session_id.to_string();
         // Flatten owner chains defensively.
         for _ in 0..8 {
-            match self.session_tab_owner.get(&current) {
+            match self.shell.workspace.tab_owner.get(&current) {
                 Some(owner) if owner != &current => current = owner.clone(),
                 _ => break,
             }
@@ -176,7 +178,7 @@ impl NyaTermApp {
                 return active.to_string();
             }
         }
-        if let Some(root) = self.session_pane_roots.get(tab_root) {
+        if let Some(root) = self.shell.workspace.pane_roots.get(tab_root) {
             if let Some(first) = root.session_ids().into_iter().next() {
                 return first;
             }

crates/nyaterm-desktop/src/features/session/session_runtime/background.rs

@@ -50,10 +50,10 @@ impl NyaTermApp {
         if !self.session.start.select_pending(&request_id) {
             return;
         }
-        self.open_tabs_menu_open = false;
-        self.new_session_menu_open = false;
-        self.selected_nav = NavItem::Workspace;
-        self.main_mode = MainMode::Workspace;
+        self.shell.chrome.open_tabs_menu_open = false;
+        self.shell.chrome.new_session_menu_open = false;
+        self.shell.navigation.selected_nav = NavItem::Workspace;
+        self.shell.navigation.main_mode = MainMode::Workspace;
         cx.notify();
     }
 
@@ -80,10 +80,10 @@ impl NyaTermApp {
         if !self.session.start.select_failed(&request_id) {
             return;
         }
-        self.open_tabs_menu_open = false;
-        self.new_session_menu_open = false;
-        self.selected_nav = NavItem::Workspace;
-        self.main_mode = MainMode::Workspace;
+        self.shell.chrome.open_tabs_menu_open = false;
+        self.shell.chrome.new_session_menu_open = false;
+        self.shell.navigation.selected_nav = NavItem::Workspace;
+        self.shell.navigation.main_mode = MainMode::Workspace;
         cx.notify();
     }
 
@@ -96,8 +96,8 @@ impl NyaTermApp {
             return;
         };
         if !self.session.start.has_failed() {
-            self.last_connect_failure_name = None;
-            self.last_connect_failure_error = None;
+            self.shell.chrome.last_connect_failure_name = None;
+            self.shell.chrome.last_connect_failure_error = None;
         }
         self.terminal.view.status = format!(
             "closed failed connection {}",
@@ -136,8 +136,8 @@ impl NyaTermApp {
         } = registration;
 
         if reconnect_session_id.is_none() {
-            self.last_connect_failure_name = None;
-            self.last_connect_failure_error = None;
+            self.shell.chrome.last_connect_failure_name = None;
+            self.shell.chrome.last_connect_failure_error = None;
         }
         self.session.start.panes.insert(
             request_id.clone(),
@@ -174,8 +174,8 @@ impl NyaTermApp {
         // Status + connecting tab already show progress; avoid full terminal decode
         // work on the click path before the worker even starts.
         let _ = append_start_log;
-        self.selected_nav = NavItem::Workspace;
-        self.main_mode = MainMode::Workspace;
+        self.shell.navigation.selected_nav = NavItem::Workspace;
+        self.shell.navigation.main_mode = MainMode::Workspace;
         cx.notify();
         request_id
     }
@@ -469,8 +469,8 @@ impl NyaTermApp {
             match event.result {
                 Ok(success) => {
                     let ui_register_started_at = Instant::now();
-                    self.last_connect_failure_name = None;
-                    self.last_connect_failure_error = None;
+                    self.shell.chrome.last_connect_failure_name = None;
+                    self.shell.chrome.last_connect_failure_error = None;
                     let session_info = success.session_info;
                     let session_id = session_info.id.clone();
                     let reconnect_session_id = pending
@@ -640,7 +640,7 @@ impl NyaTermApp {
                         self.schedule_startup_command(session_id.clone(), startup_command, cx);
                     }
                     self.apply_pending_workspace_split_for_duplicate(&session_id);
-                    self.selected_nav = NavItem::Workspace;
+                    self.shell.navigation.selected_nav = NavItem::Workspace;
                     let ui_register_duration = ui_register_started_at.elapsed();
                     let request_to_ui_duration = requested_at
                         .map(|requested_at| requested_at.elapsed())
@@ -685,8 +685,8 @@ impl NyaTermApp {
                         let _ = self.session.start.reconnect_replace_id.take();
                     }
                     if !reconnect_failure {
-                        self.last_connect_failure_name = Some(connection_name.clone());
-                        self.last_connect_failure_error = Some(error.clone());
+                        self.shell.chrome.last_connect_failure_name = Some(connection_name.clone());
+                        self.shell.chrome.last_connect_failure_error = Some(error.clone());
                     }
                     if let Some(session_id) = reconnect_session_id {
                         if self.session.metadata.contains_key(&session_id) {
@@ -725,7 +725,7 @@ impl NyaTermApp {
                             connection_name
                         ));
                     }
-                    self.selected_nav = NavItem::Workspace;
+                    self.shell.navigation.selected_nav = NavItem::Workspace;
                     let request_to_ui_duration = requested_at
                         .map(|requested_at| requested_at.elapsed())
                         .unwrap_or(worker_duration + worker_to_ui_duration);

crates/nyaterm-desktop/src/features/session/session_runtime/start.rs

@@ -80,8 +80,8 @@ impl NyaTermApp {
         if self.saved_connection_start_is_pending_or_queued(&connection) {
             self.terminal.view.status =
                 format!("{} is already connecting or queued", connection.name);
-            self.selected_nav = NavItem::Workspace;
-            self.main_mode = MainMode::Workspace;
+            self.shell.navigation.selected_nav = NavItem::Workspace;
+            self.shell.navigation.main_mode = MainMode::Workspace;
             cx.notify();
             return;
         }

crates/nyaterm-desktop/src/features/session/session_state.rs

@@ -244,10 +244,7 @@ impl NyaTermApp {
     pub(in crate::features) fn activate_session_id(&mut self, session_id: &str) -> Option<String> {
         self.session.start.active_pending = None;
         self.session.start.active_failed = None;
-        self.open_tabs_menu_open = false;
-        self.new_session_menu_open = false;
-        self.new_session_all_sessions_open = false;
-        self.new_session_group_menu_path.clear();
+        self.shell.chrome.prepare_session_switch();
         // Session switch resets terminal-output credential autofill (Tauri XTerminal remount).
         self.terminal.assist.reset_for_session_switch();
         let previous_session_id = self.session.active_id.clone();
@@ -265,7 +262,6 @@ impl NyaTermApp {
             self.transfer.queue.job_delete = None;
             self.reset_remote_runtime_for_session_switch();
         }
-        self.session_tab_scroll_into_view_pending = true;
         // Keep workspace_split mirrored to the active tab's per-tab pane root.
         self.sync_workspace_split_from_active_tab();
         self.transfer.browser.auto_sync_cwd_last_at = None;
@@ -279,9 +275,9 @@ impl NyaTermApp {
         // Transfer browser state is only needed when the transfers panel is open
         // or we already have cached browser state for this session. Skipping the
         // full reset on every activate keeps connect/switch chrome responsive.
-        let transfers_panel_visible = self.active_left_panel == Some(NavItem::Transfers)
-            || self.active_right_panel == Some(NavItem::Transfers)
-            || self.selected_nav == NavItem::Transfers;
+        let transfers_panel_visible = self.shell.panels.active_left == Some(NavItem::Transfers)
+            || self.shell.panels.active_right == Some(NavItem::Transfers)
+            || self.shell.navigation.selected_nav == NavItem::Transfers;
         if transfers_panel_visible
             || self.transfer.browser.session_cache.contains_key(session_id)
             || !self.transfer.browser.entries.is_empty()
@@ -435,7 +431,7 @@ impl NyaTermApp {
         } else {
             format!("active {}", short_id(&focus_id))
         };
-        self.selected_nav = NavItem::Workspace;
+        self.shell.navigation.selected_nav = NavItem::Workspace;
         cx.notify();
     }
 
@@ -464,8 +460,8 @@ impl NyaTermApp {
         let next_index = (active_index as isize + offset).rem_euclid(len) as usize;
         let session_id = sessions[next_index].id.clone();
         self.activate_session_id_with_surface_sync(&session_id, cx);
-        self.selected_nav = NavItem::Workspace;
-        self.main_mode = MainMode::Workspace;
+        self.shell.navigation.selected_nav = NavItem::Workspace;
+        self.shell.navigation.main_mode = MainMode::Workspace;
         self.terminal.view.status = format!("active {}", short_id(&session_id));
         cx.notify();
     }
@@ -484,49 +480,30 @@ impl NyaTermApp {
         let index = index.min(sessions.len().saturating_sub(1));
         let session_id = sessions[index].id.clone();
         self.activate_session_id_with_surface_sync(&session_id, cx);
-        self.selected_nav = NavItem::Workspace;
-        self.main_mode = MainMode::Workspace;
+        self.shell.navigation.selected_nav = NavItem::Workspace;
+        self.shell.navigation.main_mode = MainMode::Workspace;
         self.terminal.view.status = format!("active {}", short_id(&session_id));
         cx.notify();
     }
 
     pub(in crate::features) fn toggle_open_tabs_menu(&mut self, cx: &mut Context<Self>) {
-        self.open_tabs_menu_open = !self.open_tabs_menu_open;
-        if self.open_tabs_menu_open {
-            self.new_session_menu_open = false;
-            self.new_session_all_sessions_open = false;
-            self.new_session_group_menu_path.clear();
-            self.title_menu_open = None;
-        }
+        self.shell.chrome.toggle_open_tabs_menu();
         cx.notify();
     }
 
     pub(in crate::features) fn close_open_tabs_menu(&mut self, cx: &mut Context<Self>) {
-        if self.open_tabs_menu_open {
-            self.open_tabs_menu_open = false;
+        if self.shell.chrome.close_open_tabs_menu() {
             cx.notify();
         }
     }
 
     pub(in crate::features) fn toggle_new_session_menu(&mut self, cx: &mut Context<Self>) {
-        self.new_session_menu_open = !self.new_session_menu_open;
-        if self.new_session_menu_open {
-            self.open_tabs_menu_open = false;
-            self.title_menu_open = None;
-        }
-        self.new_session_all_sessions_open = false;
-        self.new_session_group_menu_path.clear();
+        self.shell.chrome.toggle_new_session_menu();
         cx.notify();
     }
 
     pub(in crate::features) fn close_new_session_menu(&mut self, cx: &mut Context<Self>) {
-        let changed = self.new_session_menu_open
-            || self.new_session_all_sessions_open
-            || !self.new_session_group_menu_path.is_empty();
-        self.new_session_menu_open = false;
-        self.new_session_all_sessions_open = false;
-        self.new_session_group_menu_path.clear();
-        if changed {
+        if self.shell.chrome.close_new_session_menu() {
             cx.notify();
         }
     }

crates/nyaterm-desktop/src/features/session/startup_restore_runtime.rs

@@ -198,7 +198,7 @@ impl NyaTermApp {
             .into_iter()
             .map(|session| {
                 let mut tab = self.serialize_open_tab_for_session(&session);
-                if let Some(root) = self.session_pane_roots.get(&session.id) {
+                if let Some(root) = self.shell.workspace.pane_roots.get(&session.id) {
                     if root.is_split() {
                         if let Some(pane_root) = self.workspace_pane_to_restorable_pane(root) {
                             tab.root = Some(pane_root);
@@ -241,14 +241,16 @@ impl NyaTermApp {
     /// entry whose `root` is a Tauri RestorablePaneNode tree (for interop).
     fn serialize_open_tabs_as_single_pane_tab(&self) -> Option<Vec<RestorableOpenTab>> {
         // Only collapse to one open_tabs entry when exactly one split tree covers every session.
-        if self.session_pane_roots.len() > 1 {
+        if self.shell.workspace.pane_roots.len() > 1 {
             return None;
         }
         let root = self
-            .session_pane_roots
+            .shell
+            .workspace
+            .pane_roots
             .values()
             .find(|root| root.is_split())
-            .or(self.workspace_split.as_ref())?;
+            .or(self.shell.workspace.split.as_ref())?;
         if !root.is_split() {
             return None;
         }
@@ -464,7 +466,7 @@ impl NyaTermApp {
         self.mark_startup_restore_complete(cx);
         // After all tabs reconnect, attempt multi-leaf then global pane layout restore.
         self.terminal.windows.restored = false;
-        self.workspace_pane_layout_restored = false;
+        self.shell.workspace.pane_layout_restored = false;
         self.try_restore_terminal_window_layout();
         // Prefer stored ui.workspace_pane_layout only when no open_tabs per-tab roots exist.
         // open_tabs[].root maps to per-tab session_pane_roots (Tauri Tab.root).
@@ -479,7 +481,7 @@ impl NyaTermApp {
         if pending_layouts.is_empty() {
             self.try_restore_workspace_pane_layout();
         } else {
-            self.workspace_pane_layout_restored = true;
+            self.shell.workspace.pane_layout_restored = true;
             for layout in pending_layouts {
                 self.apply_restorable_workspace_pane_layout(layout);
             }
@@ -498,9 +500,11 @@ impl NyaTermApp {
         }
         if self.terminal_windows_is_multi_leaf() {
             self.terminal.view.status = "restored workspace tabs and window layout".to_string();
-        } else if !self.session_pane_roots.is_empty()
+        } else if !self.shell.workspace.pane_roots.is_empty()
             || self
-                .workspace_split
+                .shell
+                .workspace
+                .split
                 .as_ref()
                 .is_some_and(|root| root.is_split())
         {
@@ -600,20 +604,23 @@ impl NyaTermApp {
             return;
         };
         // Avoid clobbering an existing distinct per-tab tree for the same root.
-        if let Some(existing) = self.session_pane_roots.get(&first) {
+        if let Some(existing) = self.shell.workspace.pane_roots.get(&first) {
             if existing != &restored {
                 // Prefer the newly restored tree from open_tabs for this root.
             }
         }
-        self.session_pane_roots.insert(first.clone(), restored);
+        self.shell
+            .workspace
+            .pane_roots
+            .insert(first.clone(), restored);
         self.rebuild_session_tab_owners();
         if self.session.active_id.is_none() {
             self.session.active_id = Some(first);
         }
         self.sync_workspace_split_from_active_tab();
-        self.workspace_pane_layout_restored = true;
-        self.selected_nav = NavItem::Workspace;
-        self.main_mode = MainMode::Workspace;
+        self.shell.workspace.pane_layout_restored = true;
+        self.shell.navigation.selected_nav = NavItem::Workspace;
+        self.shell.navigation.main_mode = MainMode::Workspace;
         self.terminal.view.status = "restored pane layout from open_tabs root".to_string();
     }
 }

crates/nyaterm-desktop/src/features/settings/security_runtime/unlock.rs

@@ -76,7 +76,7 @@ impl NyaTermApp {
     ) {
         self.security.unlock.master_required_prompt_open = false;
         self.security.unlock.pending_action = None;
-        self.settings_active_tab = SettingsTab::Security;
+        self.shell.navigation.settings.active_tab = SettingsTab::Security;
         self.open_page(NavItem::Settings, cx);
     }
 

crates/nyaterm-desktop/src/features/settings/settings_runtime/draft.rs

@@ -8,10 +8,10 @@ use crate::models::{CloudSyncSecretDraft, MainMode, NavItem, TranslationSecretDr
 
 impl NyaTermApp {
     pub(in crate::features) fn begin_settings_draft(&mut self) {
-        if self.settings_draft_snapshot.is_some() {
+        if self.shell.navigation.settings.draft_snapshot.is_some() {
             return;
         }
-        self.settings_draft_snapshot = Some(SettingsDraftSnapshot {
+        self.shell.navigation.settings.draft_snapshot = Some(SettingsDraftSnapshot {
             settings: self.settings.clone(),
             ai_settings: self.ai.settings.config.clone(),
             ai_model_draft: self.ai.settings.model_draft.clone(),
@@ -28,7 +28,7 @@ impl NyaTermApp {
     }
 
     pub(in crate::features) fn settings_draft_dirty(&self) -> bool {
-        let Some(snapshot) = self.settings_draft_snapshot.as_ref() else {
+        let Some(snapshot) = self.shell.navigation.settings.draft_snapshot.as_ref() else {
             return false;
         };
         snapshot.settings != self.settings
@@ -50,7 +50,7 @@ impl NyaTermApp {
         &mut self,
         cx: &mut Context<Self>,
     ) -> bool {
-        if self.settings_draft_snapshot.is_none() {
+        if self.shell.navigation.settings.draft_snapshot.is_none() {
             return false;
         }
         self.store_status.message = "settings draft changed".to_string();
@@ -241,10 +241,10 @@ impl NyaTermApp {
     }
 
     pub(in crate::features) fn rebase_open_settings_draft(&mut self) {
-        if self.settings_draft_snapshot.is_none() {
+        if self.shell.navigation.settings.draft_snapshot.is_none() {
             return;
         }
-        self.settings_draft_snapshot = None;
+        self.shell.navigation.settings.draft_snapshot = None;
         self.settings_master_password_enabled = self.settings.has_master_password;
         self.settings_master_password_draft.clear();
         self.begin_settings_draft();
@@ -255,7 +255,7 @@ impl NyaTermApp {
         close_after_apply: bool,
         cx: &mut Context<Self>,
     ) {
-        if self.settings_draft_snapshot.is_none() {
+        if self.shell.navigation.settings.draft_snapshot.is_none() {
             if close_after_apply {
                 self.finish_settings_page(cx);
             }
@@ -357,7 +357,7 @@ impl NyaTermApp {
                         store.save_workspace_pane_layout(None)
                     });
                 }
-                self.settings_draft_snapshot = None;
+                self.shell.navigation.settings.draft_snapshot = None;
                 self.store_status.message = "settings applied".to_string();
                 self.store_status.ready = true;
                 self.terminal.view.status = "settings applied".to_string();
@@ -378,7 +378,7 @@ impl NyaTermApp {
     }
 
     pub(in crate::features) fn cancel_settings(&mut self, cx: &mut Context<Self>) {
-        if let Some(snapshot) = self.settings_draft_snapshot.take() {
+        if let Some(snapshot) = self.shell.navigation.settings.draft_snapshot.take() {
             self.apply_gpui_settings(snapshot.settings);
             self.ai.settings.config = snapshot.ai_settings;
             self.ai.settings.model_draft = snapshot.ai_model_draft;
@@ -410,7 +410,7 @@ impl NyaTermApp {
         if self.settings_draft_dirty() {
             self.apply_settings_draft(true, cx);
         } else {
-            self.settings_draft_snapshot = None;
+            self.shell.navigation.settings.draft_snapshot = None;
             self.finish_settings_page(cx);
         }
     }
@@ -454,22 +454,30 @@ impl NyaTermApp {
         self.forget_text_inputs("ai.settings.action.");
         self.forget_text_inputs("ai.settings.manual-model.");
         self.forget_text_inputs("keyword.highlight.");
-        self.settings_window = None;
-        self.settings_window_open_pending = false;
-        if self.main_mode == MainMode::Page && self.selected_nav == NavItem::Settings {
-            self.main_mode = MainMode::Workspace;
-            self.left_sidebar_collapsed = self
-                .settings_previous_left_collapsed
+        self.shell.navigation.settings.window = None;
+        self.shell.navigation.settings.window_open_pending = false;
+        if self.shell.navigation.main_mode == MainMode::Page
+            && self.shell.navigation.selected_nav == NavItem::Settings
+        {
+            self.shell.navigation.main_mode = MainMode::Workspace;
+            self.shell.panels.left_collapsed = self
+                .shell
+                .navigation
+                .settings
+                .previous_left_collapsed
                 .take()
-                .unwrap_or_else(|| self.active_left_panel.is_none());
-            self.right_inspector_collapsed = self
-                .settings_previous_right_collapsed
+                .unwrap_or_else(|| self.shell.panels.active_left.is_none());
+            self.shell.panels.right_collapsed = self
+                .shell
+                .navigation
+                .settings
+                .previous_right_collapsed
                 .take()
-                .unwrap_or_else(|| self.active_right_panel.is_none());
+                .unwrap_or_else(|| self.shell.panels.active_right.is_none());
             self.persist_ui_layout();
         } else {
-            self.settings_previous_left_collapsed = None;
-            self.settings_previous_right_collapsed = None;
+            self.shell.navigation.settings.previous_left_collapsed = None;
+            self.shell.navigation.settings.previous_right_collapsed = None;
         }
         self.terminal.view.status = "settings closed".to_string();
         cx.notify();

crates/nyaterm-desktop/src/features/settings/settings_runtime/general_interaction.rs

@@ -24,7 +24,9 @@ impl NyaTermApp {
     ) {
         self.settings.startup_restore_window_layout = !self.settings.startup_restore_window_layout;
         self.save_general_settings(cx);
-        if !self.settings.startup_restore_window_layout && self.settings_draft_snapshot.is_none() {
+        if !self.settings.startup_restore_window_layout
+            && self.shell.navigation.settings.draft_snapshot.is_none()
+        {
             // Clear stored layouts when the user disables restore.
             let _ = ConnectionStore::open_with_portable_key_path(
                 self.runtime.config_dir(),
@@ -149,7 +151,7 @@ impl NyaTermApp {
         self.settings.interaction_command_suggestions_enabled =
             !self.settings.interaction_command_suggestions_enabled;
         if !self.settings.interaction_command_suggestions_enabled
-            && self.settings_draft_snapshot.is_none()
+            && self.shell.navigation.settings.draft_snapshot.is_none()
         {
             self.terminal.assist.clear_command_tracking();
         }

crates/nyaterm-desktop/src/features/settings/settings_runtime/terminal_remote.rs

@@ -48,7 +48,7 @@ impl NyaTermApp {
     ) {
         let next = (self.settings.terminal_scrollback_lines as i32 + delta).clamp(100, 100_000);
         self.settings.terminal_scrollback_lines = next as u32;
-        if self.settings_draft_snapshot.is_none() {
+        if self.shell.navigation.settings.draft_snapshot.is_none() {
             self.enforce_terminal_scrollback_limit();
         }
         self.save_terminal_settings(cx);

crates/nyaterm-desktop/src/features/settings_window.rs

@@ -24,10 +24,18 @@ impl SettingsWindow {
 
 impl Render for SettingsWindow {
     fn render(&mut self, window: &mut Window, cx: &mut Context<Self>) -> impl IntoElement {
-        if self.app.read(cx).settings_draft_snapshot.is_none() {
+        if self
+            .app
+            .read(cx)
+            .shell
+            .navigation
+            .settings
+            .draft_snapshot
+            .is_none()
+        {
             self.app.update(cx, |app, cx| {
-                app.settings_window = None;
-                app.settings_window_open_pending = false;
+                app.shell.navigation.settings.window = None;
+                app.shell.navigation.settings.window_open_pending = false;
                 cx.notify();
             });
             window.defer(cx, |window, _| window.remove_window());
@@ -77,7 +85,7 @@ impl Render for SettingsWindow {
 
 impl NyaTermApp {
     pub(in crate::features) fn activate_settings_window(&mut self, cx: &mut Context<Self>) -> bool {
-        let Some(handle) = self.settings_window else {
+        let Some(handle) = self.shell.navigation.settings.window else {
             return false;
         };
         let app = cx.entity();
@@ -87,8 +95,14 @@ impl NyaTermApp {
                 .is_err()
             {
                 let _ = app.update(cx, |app, cx| {
-                    if app.settings_window.is_some_and(|current| current == handle) {
-                        app.settings_window = None;
+                    if app
+                        .shell
+                        .navigation
+                        .settings
+                        .window
+                        .is_some_and(|current| current == handle)
+                    {
+                        app.shell.navigation.settings.window = None;
                         cx.notify();
                     }
                 });
@@ -101,15 +115,15 @@ impl NyaTermApp {
         if self.activate_settings_window(cx) {
             return true;
         }
-        if self.settings_window_open_pending {
+        if self.shell.navigation.settings.window_open_pending {
             return true;
         }
 
-        self.settings_window_open_pending = true;
+        self.shell.navigation.settings.window_open_pending = true;
         cx.notify();
         let app = cx.entity();
         cx.defer(move |cx| {
-            let should_open = app.read(cx).settings_window_open_pending;
+            let should_open = app.read(cx).shell.navigation.settings.window_open_pending;
             if should_open {
                 open_settings_window_now_from_app(app, cx);
             }
@@ -119,17 +133,24 @@ impl NyaTermApp {
 }
 
 fn open_settings_window_now_from_app(app: Entity<NyaTermApp>, cx: &mut App) {
-    if app.read(cx).settings_window.is_some() {
+    if app.read(cx).shell.navigation.settings.window.is_some() {
         let _ = app.update(cx, |app, cx| {
-            app.settings_window_open_pending = false;
+            app.shell.navigation.settings.window_open_pending = false;
             app.activate_settings_window(cx);
             cx.notify();
         });
         return;
     }
-    if app.read(cx).settings_draft_snapshot.is_none() {
+    if app
+        .read(cx)
+        .shell
+        .navigation
+        .settings
+        .draft_snapshot
+        .is_none()
+    {
         let _ = app.update(cx, |app, cx| {
-            app.settings_window_open_pending = false;
+            app.shell.navigation.settings.window_open_pending = false;
             cx.notify();
         });
         return;
@@ -152,8 +173,8 @@ fn open_settings_window_now_from_app(app: Entity<NyaTermApp>, cx: &mut App) {
             window.on_window_should_close(cx, move |_, cx| {
                 close_app.update(cx, |app, cx| {
                     app.cancel_settings(cx);
-                    app.settings_window = None;
-                    app.settings_window_open_pending = false;
+                    app.shell.navigation.settings.window = None;
+                    app.shell.navigation.settings.window_open_pending = false;
                 });
                 true
             });
@@ -163,19 +184,19 @@ fn open_settings_window_now_from_app(app: Entity<NyaTermApp>, cx: &mut App) {
 
     let _ = app.update(cx, |app, cx| match result {
         Ok(handle) => {
-            app.settings_window = Some(handle);
-            app.settings_window_open_pending = false;
-            app.settings_previous_left_collapsed = None;
-            app.settings_previous_right_collapsed = None;
+            app.shell.navigation.settings.window = Some(handle);
+            app.shell.navigation.settings.window_open_pending = false;
+            app.shell.navigation.settings.previous_left_collapsed = None;
+            app.shell.navigation.settings.previous_right_collapsed = None;
             cx.notify();
         }
         Err(error) => {
-            app.settings_window = None;
-            app.settings_window_open_pending = false;
-            app.main_mode = MainMode::Page;
-            app.selected_nav = crate::models::NavItem::Settings;
-            app.left_sidebar_collapsed = true;
-            app.right_inspector_collapsed = true;
+            app.shell.navigation.settings.window = None;
+            app.shell.navigation.settings.window_open_pending = false;
+            app.shell.navigation.main_mode = MainMode::Page;
+            app.shell.navigation.selected_nav = crate::models::NavItem::Settings;
+            app.shell.panels.left_collapsed = true;
+            app.shell.panels.right_collapsed = true;
             app.terminal.view.status = format!("failed to open settings window: {error}");
             cx.notify();
         }

crates/nyaterm-desktop/src/features/shell/activity_bar_runtime.rs

@@ -73,14 +73,16 @@ impl NyaTermApp {
         };
         zones
             .into_iter()
-            .any(|zone| !self.activity_bar_layout.zone(zone).is_empty())
+            .any(|zone| !self.shell.chrome.activity_bar_layout.zone(zone).is_empty())
     }
 
     pub(in crate::features) fn activity_entries_for_zone(
         &self,
         zone: ActivityBarZone,
     ) -> Vec<ActivityBarEntry> {
-        self.activity_bar_layout
+        self.shell
+            .chrome
+            .activity_bar_layout
             .zone(zone)
             .iter()
             .filter_map(|id| ActivityBarEntry::from_persistence_id(id))
@@ -88,15 +90,20 @@ impl NyaTermApp {
     }
 
     pub(in crate::features) fn sync_activity_layout_to_settings(&mut self) {
-        self.settings.ui_activity_bar_left_top = self.activity_bar_layout.left_top.clone();
-        self.settings.ui_activity_bar_left_bottom = self.activity_bar_layout.left_bottom.clone();
-        self.settings.ui_activity_bar_right_top = self.activity_bar_layout.right_top.clone();
-        self.settings.ui_activity_bar_right_bottom = self.activity_bar_layout.right_bottom.clone();
-        self.settings.ui_activity_bar_show_labels = self.activity_bar_layout.show_labels;
+        self.settings.ui_activity_bar_left_top =
+            self.shell.chrome.activity_bar_layout.left_top.clone();
+        self.settings.ui_activity_bar_left_bottom =
+            self.shell.chrome.activity_bar_layout.left_bottom.clone();
+        self.settings.ui_activity_bar_right_top =
+            self.shell.chrome.activity_bar_layout.right_top.clone();
+        self.settings.ui_activity_bar_right_bottom =
+            self.shell.chrome.activity_bar_layout.right_bottom.clone();
+        self.settings.ui_activity_bar_show_labels =
+            self.shell.chrome.activity_bar_layout.show_labels;
     }
 
     pub(in crate::features) fn apply_activity_layout_from_settings(&mut self) {
-        self.activity_bar_layout = ActivityBarLayoutState {
+        self.shell.chrome.activity_bar_layout = ActivityBarLayoutState {
             left_top: self.settings.ui_activity_bar_left_top.clone(),
             left_bottom: self.settings.ui_activity_bar_left_bottom.clone(),
             right_top: self.settings.ui_activity_bar_right_top.clone(),
@@ -110,7 +117,14 @@ impl NyaTermApp {
         let mut seen = std::collections::HashSet::new();
         for zone in ActivityBarZone::all() {
             let mut next = Vec::new();
-            for id in self.activity_bar_layout.zone(zone).iter().cloned() {
+            for id in self
+                .shell
+                .chrome
+                .activity_bar_layout
+                .zone(zone)
+                .iter()
+                .cloned()
+            {
                 if id == "fileTransfer" {
                     continue;
                 }
@@ -118,7 +132,7 @@ impl NyaTermApp {
                     next.push(id);
                 }
             }
-            *self.activity_bar_layout.zone_mut(zone) = next;
+            *self.shell.chrome.activity_bar_layout.zone_mut(zone) = next;
         }
         // Keep intentionally empty zones empty. Tauri only restores missing entries;
         // it does not repopulate a zone after the user moves its last item away.
@@ -131,15 +145,20 @@ impl NyaTermApp {
                 .cloned()
                 .collect::<Vec<_>>();
             if !missing.is_empty() {
-                self.activity_bar_layout.zone_mut(zone).extend(missing);
+                self.shell
+                    .chrome
+                    .activity_bar_layout
+                    .zone_mut(zone)
+                    .extend(missing);
                 seen.extend(defaults.zone(zone).iter().cloned());
             }
         }
     }
 
     pub(in crate::features) fn toggle_activity_bar_labels(&mut self, cx: &mut Context<Self>) {
-        self.activity_bar_layout.show_labels = !self.activity_bar_layout.show_labels;
-        self.terminal.view.status = if self.activity_bar_layout.show_labels {
+        self.shell.chrome.activity_bar_layout.show_labels =
+            !self.shell.chrome.activity_bar_layout.show_labels;
+        self.terminal.view.status = if self.shell.chrome.activity_bar_layout.show_labels {
             "activity labels shown".to_string()
         } else {
             "activity labels hidden".to_string()
@@ -156,8 +175,8 @@ impl NyaTermApp {
         event: &MouseDownEvent,
         cx: &mut Context<Self>,
     ) {
-        self.title_menu_open = None;
-        self.activity_bar_context_menu = Some(ActivityBarContextMenuState {
+        self.shell.chrome.title_menu_open = None;
+        self.shell.chrome.activity_bar_context_menu = Some(ActivityBarContextMenuState {
             entry_id,
             zone,
             index,
@@ -169,7 +188,7 @@ impl NyaTermApp {
     }
 
     pub(in crate::features) fn open_activity_bar_move_submenu(&mut self, cx: &mut Context<Self>) {
-        let Some(menu) = self.activity_bar_context_menu.as_mut() else {
+        let Some(menu) = self.shell.chrome.activity_bar_context_menu.as_mut() else {
             return;
         };
         if !menu.move_submenu_open {
@@ -179,7 +198,7 @@ impl NyaTermApp {
     }
 
     pub(in crate::features) fn close_activity_bar_context_menu(&mut self, cx: &mut Context<Self>) {
-        self.activity_bar_context_menu = None;
+        self.shell.chrome.activity_bar_context_menu = None;
         cx.notify();
     }
 
@@ -190,7 +209,8 @@ impl NyaTermApp {
         target_index: Option<usize>,
         cx: &mut Context<Self>,
     ) {
-        let Some((source_zone, source_index)) = self.activity_bar_layout.find_entry(&entry_id)
+        let Some((source_zone, source_index)) =
+            self.shell.chrome.activity_bar_layout.find_entry(&entry_id)
         else {
             self.terminal.view.status = "activity item not found".to_string();
             cx.notify();
@@ -199,14 +219,19 @@ impl NyaTermApp {
 
         // Same entry dropped on itself — no-op.
         if source_zone == target_zone {
-            let len = self.activity_bar_layout.zone(target_zone).len();
+            let len = self
+                .shell
+                .chrome
+                .activity_bar_layout
+                .zone(target_zone)
+                .len();
             let mut insert_at = target_index.unwrap_or(len);
             if source_index < insert_at {
                 insert_at = insert_at.saturating_sub(1);
             }
             insert_at = insert_at.min(len.saturating_sub(1));
             if insert_at == source_index {
-                self.activity_bar_context_menu = None;
+                self.shell.chrome.activity_bar_context_menu = None;
                 cx.notify();
                 return;
             }
@@ -214,16 +239,31 @@ impl NyaTermApp {
 
         // Remove from source.
         let removed = self
+            .shell
+            .chrome
             .activity_bar_layout
             .zone_mut(source_zone)
             .remove(source_index);
-        let mut insert_at =
-            target_index.unwrap_or_else(|| self.activity_bar_layout.zone(target_zone).len());
+        let mut insert_at = target_index.unwrap_or_else(|| {
+            self.shell
+                .chrome
+                .activity_bar_layout
+                .zone(target_zone)
+                .len()
+        });
         if source_zone == target_zone && source_index < insert_at {
             insert_at = insert_at.saturating_sub(1);
         }
-        insert_at = insert_at.min(self.activity_bar_layout.zone(target_zone).len());
-        self.activity_bar_layout
+        insert_at = insert_at.min(
+            self.shell
+                .chrome
+                .activity_bar_layout
+                .zone(target_zone)
+                .len(),
+        );
+        self.shell
+            .chrome
+            .activity_bar_layout
             .zone_mut(target_zone)
             .insert(insert_at, removed);
 
@@ -234,7 +274,7 @@ impl NyaTermApp {
             self.clear_activity_entry_from_side(&entry_id, source_side);
         }
 
-        self.activity_bar_context_menu = None;
+        self.shell.chrome.activity_bar_context_menu = None;
         self.terminal.view.status = format!(
             "moved {} to {}",
             entry_id,
@@ -254,27 +294,34 @@ impl NyaTermApp {
     fn clear_activity_entry_from_side(&mut self, entry_id: &str, side: PanelSide) {
         match side {
             PanelSide::Left => {
-                self.left_open_panels.retain(|id| id != entry_id);
+                self.shell.panels.left_open.retain(|id| id != entry_id);
                 if self
-                    .active_left_panel
+                    .shell
+                    .panels
+                    .active_left
                     .is_some_and(|item| item.persistence_id() == entry_id)
                 {
-                    self.active_left_panel = None;
+                    self.shell.panels.active_left = None;
                 }
-                if self.left_open_panels.is_empty() && self.active_left_panel.is_none() {
-                    self.left_sidebar_collapsed = true;
+                if self.shell.panels.left_open.is_empty() && self.shell.panels.active_left.is_none()
+                {
+                    self.shell.panels.left_collapsed = true;
                 }
             }
             PanelSide::Right => {
-                self.right_open_panels.retain(|id| id != entry_id);
+                self.shell.panels.right_open.retain(|id| id != entry_id);
                 if self
-                    .active_right_panel
+                    .shell
+                    .panels
+                    .active_right
                     .is_some_and(|item| item.persistence_id() == entry_id)
                 {
-                    self.active_right_panel = None;
+                    self.shell.panels.active_right = None;
                 }
-                if self.right_open_panels.is_empty() && self.active_right_panel.is_none() {
-                    self.right_inspector_collapsed = true;
+                if self.shell.panels.right_open.is_empty()
+                    && self.shell.panels.active_right.is_none()
+                {
+                    self.shell.panels.right_collapsed = true;
                 }
             }
         }
@@ -293,11 +340,11 @@ impl NyaTermApp {
                 self.open_panel(item, cx);
                 if !cfg!(target_os = "macos") {
                     match side {
-                        Some(PanelSide::Left) if self.last_viewport_size.0 < 1024. => {
-                            self.mobile_left_open = true;
+                        Some(PanelSide::Left) if self.shell.viewport.size.0 < 1024. => {
+                            self.shell.panels.mobile_left_open = true;
                         }
-                        Some(PanelSide::Right) if self.last_viewport_size.0 < 768. => {
-                            self.mobile_right_open = true;
+                        Some(PanelSide::Right) if self.shell.viewport.size.0 < 768. => {
+                            self.shell.panels.mobile_right_open = true;
                         }
                         _ => {}
                     }
@@ -327,11 +374,11 @@ impl NyaTermApp {
                 self.open_panel(NavItem::Recording, cx);
                 if !cfg!(target_os = "macos") {
                     match side {
-                        Some(PanelSide::Left) if self.last_viewport_size.0 < 1024. => {
-                            self.mobile_left_open = true;
+                        Some(PanelSide::Left) if self.shell.viewport.size.0 < 1024. => {
+                            self.shell.panels.mobile_left_open = true;
                         }
-                        Some(PanelSide::Right) if self.last_viewport_size.0 < 768. => {
-                            self.mobile_right_open = true;
+                        Some(PanelSide::Right) if self.shell.viewport.size.0 < 768. => {
+                            self.shell.panels.mobile_right_open = true;
                         }
                         _ => {}
                     }
@@ -345,7 +392,8 @@ impl NyaTermApp {
     pub(in crate::features) fn activity_entry_selected(&self, entry: ActivityBarEntry) -> bool {
         match entry {
             ActivityBarEntry::Panel(NavItem::Settings) => {
-                self.settings_window.is_some() || self.main_mode == MainMode::Page
+                self.shell.navigation.settings.window.is_some()
+                    || self.shell.navigation.main_mode == MainMode::Page
             }
             ActivityBarEntry::Panel(item) => self.panel_entry_selected(item),
             ActivityBarEntry::QuickCommands => {
@@ -365,13 +413,13 @@ impl NyaTermApp {
         let Some(side) = self.panel_side_for_item(item) else {
             return false;
         };
-        if self.panel_multi_open {
+        if self.shell.panels.multi_open {
             let id = item.persistence_id();
             self.side_open_panel_ids(side).iter().any(|open| open == id)
                 || self.side_overlay_panel(side) == Some(item)
                 || match side {
-                    PanelSide::Left => self.active_left_panel == Some(item),
-                    PanelSide::Right => self.active_right_panel == Some(item),
+                    PanelSide::Left => self.shell.panels.active_left == Some(item),
+                    PanelSide::Right => self.shell.panels.active_right == Some(item),
                 }
         } else {
             match side {

crates/nyaterm-desktop/src/features/shell/event_pump/helpers.rs

@@ -174,10 +174,6 @@ pub(super) fn window_geometry_churn_active(
     })
 }
 
-pub(super) fn title_drag_active(title_drag_active_until: Option<Instant>, now: Instant) -> bool {
-    title_drag_active_until.is_some_and(|until| now < until)
-}
-
 pub(super) fn connect_settle_active(until: Option<Instant>, now: Instant) -> bool {
     until.is_some_and(|until| now < until)
 }
@@ -439,7 +435,7 @@ mod tests {
         terminal_input_idle_remaining_delay, terminal_log_plain_text,
         terminal_output_dropped_marker, terminal_performance_tick_session_ids,
         terminal_render_work_pressure_active, terminal_user_scroll_frame_apply_pending,
-        title_drag_active, viewport_change_terminal_session_ids, window_geometry_churn_active,
+        viewport_change_terminal_session_ids, window_geometry_churn_active,
     };
 
     #[test]
@@ -545,14 +541,6 @@ mod tests {
         ));
     }
 
-    #[test]
-    fn title_drag_active_until_deadline() {
-        let now = Instant::now();
-        assert!(!title_drag_active(None, now));
-        assert!(title_drag_active(Some(now + Duration::from_millis(1)), now));
-        assert!(!title_drag_active(Some(now), now));
-    }
-
     #[test]
     fn connect_settle_active_until_deadline() {
         let now = Instant::now();

crates/nyaterm-desktop/src/features/shell/event_pump/mod.rs

@@ -10,7 +10,7 @@ use crate::features::shell::event_pump::helpers::{
     connect_settle_active, connect_settle_deadline, diagnostic_log_due,
     pending_session_status_message, remote_refresh_due, runtime_output_pressure_active_from_counts,
     runtime_tick_interval_for_pressure, runtime_ui_notify_allowed,
-    terminal_cell_metrics_refresh_needed, terminal_input_idle_remaining_delay, title_drag_active,
+    terminal_cell_metrics_refresh_needed, terminal_input_idle_remaining_delay,
     viewport_change_terminal_session_ids, window_geometry_churn_active,
 };
 use crate::features::{
@@ -59,13 +59,14 @@ impl NyaTermApp {
         window: &mut Window,
         cx: &mut Context<Self>,
     ) -> bool {
-        let before_viewport = self.last_viewport_size;
         let before_metrics = self.terminal.layout.cell_metrics;
         let vs = window.viewport_size();
-        self.last_viewport_size = (f32::from(vs.width), f32::from(vs.height));
-        if self.last_viewport_size != before_viewport {
+        let viewport_changed = self
+            .shell
+            .viewport
+            .update_size((f32::from(vs.width), f32::from(vs.height)), Instant::now());
+        if viewport_changed {
             // Geometry churn (resize / some window managers during move).
-            self.last_viewport_change_at = Some(Instant::now());
             self.notify_terminal_surfaces_for_viewport_change(cx);
         }
         if terminal_cell_metrics_refresh_needed(self.terminal.layout.cell_metrics) {
@@ -76,8 +77,7 @@ impl NyaTermApp {
             self.resize_all_known_terminal_surfaces();
             self.refresh_visible_terminal_surfaces(cx);
         }
-        self.last_viewport_size != before_viewport
-            || self.terminal.layout.cell_metrics != before_metrics
+        viewport_changed || self.terminal.layout.cell_metrics != before_metrics
     }
 
     fn notify_terminal_surfaces_for_viewport_change(&mut self, cx: &mut Context<Self>) {
@@ -219,11 +219,13 @@ impl NyaTermApp {
     }
 
     pub(in crate::features) fn mark_title_drag_activity(&mut self) {
-        self.title_drag_active_until = Some(Instant::now() + TITLE_DRAG_ACTIVE_HOLD);
+        self.shell
+            .viewport
+            .mark_title_drag(Instant::now(), TITLE_DRAG_ACTIVE_HOLD);
     }
 
     pub(in crate::features) fn title_drag_active(&self, now: Instant) -> bool {
-        title_drag_active(self.title_drag_active_until, now)
+        self.shell.viewport.title_drag_active(now)
     }
 
     pub(in crate::features) fn should_log_slow_diagnostic(
@@ -305,7 +307,7 @@ impl NyaTermApp {
         // idle cadence so full plane ticks do not stack on compositor paints.
         let now = Instant::now();
         if self.title_drag_active(now)
-            || window_geometry_churn_active(self.last_viewport_change_at, now)
+            || window_geometry_churn_active(self.shell.viewport.last_change_at, now)
         {
             return RUNTIME_IDLE_TICK_INTERVAL;
         }
@@ -323,7 +325,7 @@ impl NyaTermApp {
         if !self.terminal.view.runtime.event_pump_started {
             return false;
         }
-        if self.last_viewport_size != viewport_size
+        if self.shell.viewport.size != viewport_size
             || terminal_cell_metrics_refresh_needed(self.terminal.layout.cell_metrics)
         {
             return true;

crates/nyaterm-desktop/src/features/shell/event_pump/planes.rs

@@ -161,7 +161,7 @@ impl NyaTermApp {
             }
             return true;
         }
-        let geometry_churn = window_geometry_churn_active(self.last_viewport_change_at, now);
+        let geometry_churn = window_geometry_churn_active(self.shell.viewport.last_change_at, now);
         let calm_tick = self.runtime_quiet_tick_allowed();
         if geometry_churn && calm_tick {
             dirty |= self.drive_pending_focus(window, cx);
@@ -603,7 +603,7 @@ impl NyaTermApp {
         // Idle-plane work does not drain output; one pressure sample is enough for the stage.
         let output_pressure = self.runtime_output_pressure_active();
         let now = Instant::now();
-        let geometry_churn = window_geometry_churn_active(self.last_viewport_change_at, now);
+        let geometry_churn = window_geometry_churn_active(self.shell.viewport.last_change_at, now);
         let connect_settle =
             connect_settle_active(self.terminal.view.runtime.connect_settle_until, now);
         // Geometry churn / connect settle: keep focus only (no remote/layout/DB).

crates/nyaterm-desktop/src/features/shell/global_shortcut_runtime.rs

@@ -32,7 +32,7 @@ impl NyaTermApp {
 
         // Dismiss strip menus with Escape (Tauri dropdown dismiss).
         if event.keystroke.key.as_str() == "escape"
-            && (self.open_tabs_menu_open || self.new_session_menu_open)
+            && (self.shell.chrome.open_tabs_menu_open || self.shell.chrome.new_session_menu_open)
         {
             self.close_open_tabs_menu(cx);
             self.close_new_session_menu(cx);

crates/nyaterm-desktop/src/features/shell/mod.rs

@@ -20,7 +20,7 @@ pub(in crate::features) use activity_bar_runtime::{
 pub(in crate::features) use appearance::{
     appearance_font_options, appearance_font_stack, gpui_code_font_family,
 };
-pub(in crate::features) use state::ShellFeatureState;
+pub(in crate::features) use state::{ShellFeatureInit, ShellFeatureState};
 pub(in crate::features) use tab_mouse::{
     ChromeTooltip, SessionTabDragPayload, SessionTabDragPreview, SessionTabTooltip,
     TAB_MOUSE_ACTIONS, TabMouseActionTarget,

crates/nyaterm-desktop/src/features/shell/navigation_runtime.rs

@@ -7,23 +7,35 @@ impl NyaTermApp {
     pub(in crate::features) fn open_page(&mut self, item: NavItem, cx: &mut Context<Self>) {
         if item == NavItem::Settings || item.opens_settings() {
             self.begin_settings_draft();
-            if let Some(group) = self.settings_active_tab.expandable_group_id() {
-                self.settings_expanded_groups.insert(group.to_string());
+            if let Some(group) = self
+                .shell
+                .navigation
+                .settings
+                .active_tab
+                .expandable_group_id()
+            {
+                self.shell
+                    .navigation
+                    .settings
+                    .expanded_groups
+                    .insert(group.to_string());
             }
-            if self.main_mode != MainMode::Page {
-                self.settings_previous_left_collapsed = Some(self.left_sidebar_collapsed);
-                self.settings_previous_right_collapsed = Some(self.right_inspector_collapsed);
+            if self.shell.navigation.main_mode != MainMode::Page {
+                self.shell.navigation.settings.previous_left_collapsed =
+                    Some(self.shell.panels.left_collapsed);
+                self.shell.navigation.settings.previous_right_collapsed =
+                    Some(self.shell.panels.right_collapsed);
             }
             if self.open_settings_window(cx) {
-                self.main_mode = MainMode::Workspace;
+                self.shell.navigation.main_mode = MainMode::Workspace;
                 self.terminal.view.status = "settings opened".to_string();
                 cx.notify();
                 return;
             }
-            self.main_mode = MainMode::Page;
-            self.selected_nav = NavItem::Settings;
-            self.left_sidebar_collapsed = true;
-            self.right_inspector_collapsed = true;
+            self.shell.navigation.main_mode = MainMode::Page;
+            self.shell.navigation.selected_nav = NavItem::Settings;
+            self.shell.panels.left_collapsed = true;
+            self.shell.panels.right_collapsed = true;
             self.terminal.view.status = "settings opened".to_string();
             cx.notify();
             return;
@@ -43,14 +55,14 @@ impl NyaTermApp {
             return;
         }
 
-        if self.panel_multi_open && self.panel_side_for_item(item).is_some() {
+        if self.shell.panels.multi_open && self.panel_side_for_item(item).is_some() {
             self.open_or_toggle_panel(item, cx);
             return;
         }
 
-        self.main_mode = MainMode::Workspace;
-        self.selected_nav = item;
-        self.right_focus = if item == NavItem::Recording {
+        self.shell.navigation.main_mode = MainMode::Workspace;
+        self.shell.navigation.selected_nav = item;
+        self.shell.panels.right_focus = if item == NavItem::Recording {
             RightFocus::Recording
         } else {
             RightFocus::Default
@@ -58,35 +70,35 @@ impl NyaTermApp {
 
         match self.panel_side_for_item(item) {
             Some(PanelSide::Left) => {
-                let already_open =
-                    self.active_left_panel == Some(item) && !self.left_sidebar_collapsed;
+                let already_open = self.shell.panels.active_left == Some(item)
+                    && !self.shell.panels.left_collapsed;
                 if already_open {
-                    self.left_sidebar_collapsed = true;
-                    self.active_left_panel = None;
+                    self.shell.panels.left_collapsed = true;
+                    self.shell.panels.active_left = None;
                     self.terminal.view.status = format!("{} closed", item.label());
                 } else {
-                    self.active_left_panel = Some(item);
-                    self.left_sidebar_collapsed = false;
+                    self.shell.panels.active_left = Some(item);
+                    self.shell.panels.left_collapsed = false;
                     self.terminal.view.status = format!("{} opened", item.label());
                 }
             }
             Some(PanelSide::Right) => {
-                let already_open =
-                    self.active_right_panel == Some(item) && !self.right_inspector_collapsed;
+                let already_open = self.shell.panels.active_right == Some(item)
+                    && !self.shell.panels.right_collapsed;
                 if already_open {
-                    self.right_inspector_collapsed = true;
-                    self.active_right_panel = None;
-                    self.right_focus = RightFocus::Default;
+                    self.shell.panels.right_collapsed = true;
+                    self.shell.panels.active_right = None;
+                    self.shell.panels.right_focus = RightFocus::Default;
                     self.terminal.view.status = format!("{} closed", item.label());
                 } else {
-                    self.active_right_panel = Some(item);
-                    self.right_inspector_collapsed = false;
+                    self.shell.panels.active_right = Some(item);
+                    self.shell.panels.right_collapsed = false;
                     self.terminal.view.status = format!("{} opened", item.label());
                 }
             }
             None => {
-                self.left_sidebar_collapsed = false;
-                self.right_inspector_collapsed = false;
+                self.shell.panels.left_collapsed = false;
+                self.shell.panels.right_collapsed = false;
             }
         }
 
@@ -95,21 +107,21 @@ impl NyaTermApp {
     }
 
     pub(in crate::features) fn ensure_panel_open(&mut self, item: NavItem) {
-        if self.panel_multi_open && self.panel_side_for_item(item).is_some() {
+        if self.shell.panels.multi_open && self.panel_side_for_item(item).is_some() {
             self.ensure_panel_in_stack(item);
             return;
         }
-        self.main_mode = MainMode::Workspace;
-        self.selected_nav = item;
+        self.shell.navigation.main_mode = MainMode::Workspace;
+        self.shell.navigation.selected_nav = item;
         match self.panel_side_for_item(item) {
             Some(PanelSide::Left) => {
-                self.active_left_panel = Some(item);
-                self.left_sidebar_collapsed = false;
+                self.shell.panels.active_left = Some(item);
+                self.shell.panels.left_collapsed = false;
             }
             Some(PanelSide::Right) => {
-                self.active_right_panel = Some(item);
-                self.right_inspector_collapsed = false;
-                self.right_focus = if item == NavItem::Recording {
+                self.shell.panels.active_right = Some(item);
+                self.shell.panels.right_collapsed = false;
+                self.shell.panels.right_focus = if item == NavItem::Recording {
                     RightFocus::Recording
                 } else {
                     RightFocus::Default
@@ -124,34 +136,40 @@ impl NyaTermApp {
     }
 
     pub(in crate::features) fn toggle_left_sidebar(&mut self, cx: &mut Context<Self>) {
-        if self.panel_multi_open {
+        if self.shell.panels.multi_open {
             if self.left_side_open() {
-                self.left_open_panels.clear();
-                self.active_left_panel = None;
-                self.left_sidebar_collapsed = true;
+                self.shell.panels.left_open.clear();
+                self.shell.panels.active_left = None;
+                self.shell.panels.left_collapsed = true;
                 self.terminal.view.status = "left sidebar collapsed".to_string();
             } else if let Some(panel) = self
+                .shell
+                .chrome
                 .activity_bar_layout
                 .first_panel_on_side(PanelSide::Left)
             {
-                self.active_left_panel = Some(panel);
-                self.left_open_panels.clear();
+                self.shell.panels.active_left = Some(panel);
+                self.shell.panels.left_open.clear();
                 if Self::is_stackable_panel_id(panel.persistence_id()) {
-                    self.left_open_panels
+                    self.shell
+                        .panels
+                        .left_open
                         .push(panel.persistence_id().to_string());
                 }
-                self.left_sidebar_collapsed = false;
+                self.shell.panels.left_collapsed = false;
                 self.terminal.view.status = "left sidebar expanded".to_string();
             }
-        } else if self.left_sidebar_collapsed || self.active_left_panel.is_none() {
-            self.active_left_panel = self
+        } else if self.shell.panels.left_collapsed || self.shell.panels.active_left.is_none() {
+            self.shell.panels.active_left = self
+                .shell
+                .chrome
                 .activity_bar_layout
                 .first_panel_on_side(PanelSide::Left);
-            self.left_sidebar_collapsed = false;
+            self.shell.panels.left_collapsed = false;
             self.terminal.view.status = "left sidebar expanded".to_string();
         } else {
-            self.active_left_panel = None;
-            self.left_sidebar_collapsed = true;
+            self.shell.panels.active_left = None;
+            self.shell.panels.left_collapsed = true;
             self.terminal.view.status = "left sidebar collapsed".to_string();
         }
         self.persist_ui_layout();
@@ -159,34 +177,40 @@ impl NyaTermApp {
     }
 
     pub(in crate::features) fn toggle_right_inspector(&mut self, cx: &mut Context<Self>) {
-        if self.panel_multi_open {
+        if self.shell.panels.multi_open {
             if self.right_side_open() {
-                self.right_open_panels.clear();
-                self.active_right_panel = None;
-                self.right_inspector_collapsed = true;
+                self.shell.panels.right_open.clear();
+                self.shell.panels.active_right = None;
+                self.shell.panels.right_collapsed = true;
                 self.terminal.view.status = "right sidebar collapsed".to_string();
             } else if let Some(panel) = self
+                .shell
+                .chrome
                 .activity_bar_layout
                 .first_panel_on_side(PanelSide::Right)
             {
-                self.active_right_panel = Some(panel);
-                self.right_open_panels.clear();
+                self.shell.panels.active_right = Some(panel);
+                self.shell.panels.right_open.clear();
                 if Self::is_stackable_panel_id(panel.persistence_id()) {
-                    self.right_open_panels
+                    self.shell
+                        .panels
+                        .right_open
                         .push(panel.persistence_id().to_string());
                 }
-                self.right_inspector_collapsed = false;
+                self.shell.panels.right_collapsed = false;
                 self.terminal.view.status = "right sidebar expanded".to_string();
             }
-        } else if self.right_inspector_collapsed || self.active_right_panel.is_none() {
-            self.active_right_panel = self
+        } else if self.shell.panels.right_collapsed || self.shell.panels.active_right.is_none() {
+            self.shell.panels.active_right = self
+                .shell
+                .chrome
                 .activity_bar_layout
                 .first_panel_on_side(PanelSide::Right);
-            self.right_inspector_collapsed = false;
+            self.shell.panels.right_collapsed = false;
             self.terminal.view.status = "right sidebar expanded".to_string();
         } else {
-            self.active_right_panel = None;
-            self.right_inspector_collapsed = true;
+            self.shell.panels.active_right = None;
+            self.shell.panels.right_collapsed = true;
             self.terminal.view.status = "right sidebar collapsed".to_string();
         }
         self.persist_ui_layout();
@@ -194,46 +218,50 @@ impl NyaTermApp {
     }
 
     pub(in crate::features) fn toggle_mobile_left_drawer(&mut self, cx: &mut Context<Self>) {
-        if self.mobile_left_open {
-            self.mobile_left_open = false;
+        if self.shell.panels.mobile_left_open {
+            self.shell.panels.mobile_left_open = false;
         } else {
-            if self.active_left_panel.is_none() {
-                self.active_left_panel = self
+            if self.shell.panels.active_left.is_none() {
+                self.shell.panels.active_left = self
+                    .shell
+                    .chrome
                     .activity_bar_layout
                     .first_panel_on_side(PanelSide::Left);
             }
-            self.left_sidebar_collapsed = false;
-            self.mobile_left_open = true;
+            self.shell.panels.left_collapsed = false;
+            self.shell.panels.mobile_left_open = true;
         }
         cx.notify();
     }
 
     pub(in crate::features) fn toggle_mobile_right_drawer(&mut self, cx: &mut Context<Self>) {
-        if self.mobile_right_open {
-            self.mobile_right_open = false;
+        if self.shell.panels.mobile_right_open {
+            self.shell.panels.mobile_right_open = false;
         } else {
-            if self.active_right_panel.is_none() {
-                self.active_right_panel = self
+            if self.shell.panels.active_right.is_none() {
+                self.shell.panels.active_right = self
+                    .shell
+                    .chrome
                     .activity_bar_layout
                     .first_panel_on_side(PanelSide::Right);
             }
-            self.right_inspector_collapsed = false;
-            self.mobile_right_open = true;
+            self.shell.panels.right_collapsed = false;
+            self.shell.panels.mobile_right_open = true;
         }
         cx.notify();
     }
 
     pub(in crate::features) fn current_left_panel(&self) -> Option<NavItem> {
-        if self.left_sidebar_collapsed {
+        if self.shell.panels.left_collapsed {
             return None;
         }
-        if self.panel_multi_open {
+        if self.shell.panels.multi_open {
             if self.side_overlay_panel(PanelSide::Left).is_some()
                 || !self.side_open_panel_ids(PanelSide::Left).is_empty()
             {
                 return self
                     .side_overlay_panel(PanelSide::Left)
-                    .or(self.active_left_panel)
+                    .or(self.shell.panels.active_left)
                     .or_else(|| {
                         self.side_open_panel_ids(PanelSide::Left)
                             .first()
@@ -242,52 +270,55 @@ impl NyaTermApp {
             }
             return None;
         }
-        self.active_left_panel
+        self.shell.panels.active_left
     }
 
     pub(in crate::features) fn current_right_panel(&self) -> Option<NavItem> {
-        if self.right_inspector_collapsed {
+        if self.shell.panels.right_collapsed {
             return None;
         }
-        if self.panel_multi_open {
+        if self.shell.panels.multi_open {
             if self.side_overlay_panel(PanelSide::Right).is_some()
                 || !self.side_open_panel_ids(PanelSide::Right).is_empty()
             {
                 return self
                     .side_overlay_panel(PanelSide::Right)
-                    .or(self.active_right_panel)
+                    .or(self.shell.panels.active_right)
                     .or_else(|| {
                         self.side_open_panel_ids(PanelSide::Right)
                             .first()
                             .and_then(|id| NavItem::from_persistence_id(id))
                     })
-                    .or(if self.right_focus == RightFocus::Recording {
+                    .or(if self.shell.panels.right_focus == RightFocus::Recording {
                         Some(NavItem::Recording)
                     } else {
                         None
                     });
             }
-            return if self.right_focus == RightFocus::Recording {
+            return if self.shell.panels.right_focus == RightFocus::Recording {
                 Some(NavItem::Recording)
             } else {
                 None
             };
         }
-        self.active_right_panel
-            .or(if self.right_focus == RightFocus::Recording {
+        self.shell.panels.active_right.or(
+            if self.shell.panels.right_focus == RightFocus::Recording {
                 Some(NavItem::Recording)
             } else {
                 None
-            })
+            },
+        )
     }
 
     pub(in crate::features) fn left_side_open(&self) -> bool {
         self.current_left_panel().is_some()
-            || (self.panel_multi_open && !self.side_open_panel_ids(PanelSide::Left).is_empty())
+            || (self.shell.panels.multi_open
+                && !self.side_open_panel_ids(PanelSide::Left).is_empty())
     }
 
     pub(in crate::features) fn right_side_open(&self) -> bool {
         self.current_right_panel().is_some()
-            || (self.panel_multi_open && !self.side_open_panel_ids(PanelSide::Right).is_empty())
+            || (self.shell.panels.multi_open
+                && !self.side_open_panel_ids(PanelSide::Right).is_empty())
     }
 }

crates/nyaterm-desktop/src/features/shell/panel_resize_runtime.rs

@@ -6,14 +6,10 @@ use nyaterm_core::ConnectionStore;
 
 use crate::features::NyaTermApp;
 use crate::models::{
-    BottomPanelMode, NavItem, PanelResizeSide, PanelResizeState, PanelSide,
-    TransferHeightResizeState, panel_collapsed_from_persistence,
+    BottomPanelMode, NavItem, PanelResizeSide, PanelSide, TransferHeightResizeState,
+    panel_collapsed_from_persistence,
 };
 
-const LEFT_PANEL_MIN: f32 = 160.;
-const LEFT_PANEL_MAX: f32 = 720.;
-const RIGHT_PANEL_MIN: f32 = 200.;
-const RIGHT_PANEL_MAX: f32 = 720.;
 const QUICK_CMD_HEIGHT_MIN: f32 = 36.;
 const SERIAL_SEND_HEIGHT_MIN: f32 = 60.;
 const BOTTOM_PANEL_HEIGHT_MAX: f32 = 520.;
@@ -32,15 +28,7 @@ impl NyaTermApp {
         event: &MouseDownEvent,
         cx: &mut Context<Self>,
     ) {
-        let start_width = match side {
-            PanelResizeSide::Left => px(self.left_panel_width),
-            PanelResizeSide::Right => px(self.right_panel_width),
-        };
-        self.panel_resize = Some(PanelResizeState {
-            side,
-            start_x: event.position.x,
-            start_width,
-        });
+        self.shell.panels.start_resize(side, event.position.x);
         self.terminal.view.status = match side {
             PanelResizeSide::Left => "resizing left panel".to_string(),
             PanelResizeSide::Right => "resizing right panel".to_string(),
@@ -53,22 +41,16 @@ impl NyaTermApp {
         event: &MouseMoveEvent,
         cx: &mut Context<Self>,
     ) {
-        let Some(state) = self.panel_resize else {
+        let Some((side, width)) = self.shell.panels.update_resize(event.position.x) else {
             return;
         };
-        let delta = f32::from(event.position.x - state.start_x);
-        let start = f32::from(state.start_width);
-        match state.side {
+        match side {
             PanelResizeSide::Left => {
-                self.left_panel_width = (start + delta).clamp(LEFT_PANEL_MIN, LEFT_PANEL_MAX);
-                self.terminal.view.status =
-                    format!("left panel: {:.0}px", self.left_panel_width.round());
+                self.terminal.view.status = format!("left panel: {:.0}px", width.round());
             }
             PanelResizeSide::Right => {
                 // Right handle sits on the left edge of the right panel: drag left grows width.
-                self.right_panel_width = (start - delta).clamp(RIGHT_PANEL_MIN, RIGHT_PANEL_MAX);
-                self.terminal.view.status =
-                    format!("right panel: {:.0}px", self.right_panel_width.round());
+                self.terminal.view.status = format!("right panel: {:.0}px", width.round());
             }
         }
         cx.notify();
@@ -79,12 +61,12 @@ impl NyaTermApp {
         _event: &MouseUpEvent,
         cx: &mut Context<Self>,
     ) {
-        if self.panel_resize.take().is_some() {
+        if self.shell.panels.finish_resize() {
             self.persist_panel_widths();
             self.terminal.view.status = format!(
                 "panel sizes L{:.0}/R{:.0}",
-                self.left_panel_width.round(),
-                self.right_panel_width.round()
+                self.shell.panels.left_width.round(),
+                self.shell.panels.right_width.round()
             );
             cx.notify();
         }
@@ -95,34 +77,34 @@ impl NyaTermApp {
     }
 
     pub(in crate::features) fn apply_ui_layout_from_settings(&mut self) {
-        self.left_panel_width = self.settings.ui_left_panel_width as f32;
-        self.right_panel_width = self.settings.ui_right_panel_width as f32;
+        self.shell.panels.left_width = self.settings.ui_left_panel_width as f32;
+        self.shell.panels.right_width = self.settings.ui_right_panel_width as f32;
         self.transfer.panel.height = self.settings.ui_transfer_height as f32;
         self.shell.bottom_panel.quick_commands_height = self.settings.ui_quick_cmd_height as f32;
         self.shell.bottom_panel.command_send_height = self.settings.ui_serial_send_height as f32;
         self.apply_activity_layout_from_settings();
-        self.active_left_panel = self
+        self.shell.panels.active_left = self
             .settings
             .ui_active_left_panel
             .as_deref()
             .and_then(NavItem::from_persistence_id)
             .filter(|item| self.panel_side_for_item(*item) == Some(PanelSide::Left));
-        self.active_right_panel = self
+        self.shell.panels.active_right = self
             .settings
             .ui_active_right_panel
             .as_deref()
             .and_then(NavItem::from_persistence_id)
             .filter(|item| self.panel_side_for_item(*item) == Some(PanelSide::Right));
-        self.left_sidebar_collapsed = panel_collapsed_from_persistence(
+        self.shell.panels.left_collapsed = panel_collapsed_from_persistence(
             self.settings.ui_left_panel_collapsed,
             self.settings.ui_panel_multi_open,
-            self.active_left_panel.is_some(),
+            self.shell.panels.active_left.is_some(),
             !self.settings.ui_left_open_panels.is_empty(),
         );
-        self.right_inspector_collapsed = panel_collapsed_from_persistence(
+        self.shell.panels.right_collapsed = panel_collapsed_from_persistence(
             self.settings.ui_right_panel_collapsed,
             self.settings.ui_panel_multi_open,
-            self.active_right_panel.is_some(),
+            self.shell.panels.active_right.is_some(),
             !self.settings.ui_right_open_panels.is_empty(),
         );
         self.apply_panel_stack_from_settings();
@@ -132,9 +114,10 @@ impl NyaTermApp {
     }
 
     pub(in crate::features) fn persist_ui_layout(&mut self) {
-        self.settings.ui_left_panel_width = self.left_panel_width.round().clamp(160., 720.) as u32;
+        self.settings.ui_left_panel_width =
+            self.shell.panels.left_width.round().clamp(160., 720.) as u32;
         self.settings.ui_right_panel_width =
-            self.right_panel_width.round().clamp(200., 720.) as u32;
+            self.shell.panels.right_width.round().clamp(200., 720.) as u32;
         self.settings.ui_transfer_height =
             self.transfer.panel.height.round().clamp(60., 600.) as u32;
         self.settings.ui_quick_cmd_height =
@@ -150,13 +133,17 @@ impl NyaTermApp {
                 .round()
                 .clamp(SERIAL_SEND_HEIGHT_MIN, BOTTOM_PANEL_HEIGHT_MAX) as u32;
         self.settings.ui_active_left_panel = self
-            .active_left_panel
+            .shell
+            .panels
+            .active_left
             .map(|item| item.persistence_id().to_string());
         self.settings.ui_active_right_panel = self
-            .active_right_panel
+            .shell
+            .panels
+            .active_right
             .map(|item| item.persistence_id().to_string());
-        self.settings.ui_left_panel_collapsed = self.left_sidebar_collapsed;
-        self.settings.ui_right_panel_collapsed = self.right_inspector_collapsed;
+        self.settings.ui_left_panel_collapsed = self.shell.panels.left_collapsed;
+        self.settings.ui_right_panel_collapsed = self.shell.panels.right_collapsed;
         self.settings.ui_saved_connections_sort_mode = self
             .connection_state
             .list_sort_mode()

crates/nyaterm-desktop/src/features/shell/panel_stack_runtime.rs

@@ -10,8 +10,8 @@ use nyaterm_core::{AgentCommandExecutionMode, truncate_preview};
 
 use crate::features::{ChromeTooltip, NyaTermApp, TextInputSetup, panel_header_with_actions};
 use crate::models::{
-    ActivityBarZone, MainMode, NavItem, NetworkTab, PanelSide, PanelStackResizeState, RightFocus,
-    SecurityAuthTab, SettingsTab,
+    ActivityBarZone, MainMode, NavItem, NetworkTab, PanelSide, RightFocus, SecurityAuthTab,
+    SettingsTab,
 };
 use crate::theme::ThemePalette;
 
@@ -28,41 +28,45 @@ impl NyaTermApp {
     }
 
     pub(in crate::features) fn toggle_panel_multi_open(&mut self, cx: &mut Context<Self>) {
-        self.panel_multi_open = !self.panel_multi_open;
-        if self.panel_multi_open {
-            if self.left_open_panels.is_empty() {
-                if let Some(panel) = self.active_left_panel {
+        self.shell.panels.multi_open = !self.shell.panels.multi_open;
+        if self.shell.panels.multi_open {
+            if self.shell.panels.left_open.is_empty() {
+                if let Some(panel) = self.shell.panels.active_left {
                     let id = panel.persistence_id().to_string();
                     if Self::is_stackable_panel_id(&id) {
-                        self.left_open_panels.push(id);
+                        self.shell.panels.left_open.push(id);
                     }
                 }
             }
-            if self.right_open_panels.is_empty() {
-                if let Some(panel) = self.active_right_panel {
+            if self.shell.panels.right_open.is_empty() {
+                if let Some(panel) = self.shell.panels.active_right {
                     let id = panel.persistence_id().to_string();
                     if Self::is_stackable_panel_id(&id) {
-                        self.right_open_panels.push(id);
+                        self.shell.panels.right_open.push(id);
                     }
                 }
             }
             self.terminal.view.status = "multi-open panels enabled".to_string();
         } else {
             // Collapse to active-only mode.
-            if self.active_left_panel.is_none() {
-                self.active_left_panel = self
-                    .left_open_panels
+            if self.shell.panels.active_left.is_none() {
+                self.shell.panels.active_left = self
+                    .shell
+                    .panels
+                    .left_open
                     .first()
                     .and_then(|id| NavItem::from_persistence_id(id));
             }
-            if self.active_right_panel.is_none() {
-                self.active_right_panel = self
-                    .right_open_panels
+            if self.shell.panels.active_right.is_none() {
+                self.shell.panels.active_right = self
+                    .shell
+                    .panels
+                    .right_open
                     .first()
                     .and_then(|id| NavItem::from_persistence_id(id));
             }
-            self.left_open_panels.clear();
-            self.right_open_panels.clear();
+            self.shell.panels.left_open.clear();
+            self.shell.panels.right_open.clear();
             self.terminal.view.status = "single panel mode".to_string();
         }
         self.persist_ui_layout();
@@ -70,10 +74,10 @@ impl NyaTermApp {
     }
 
     pub(in crate::features) fn side_open_panel_ids(&self, side: PanelSide) -> Vec<String> {
-        if !self.panel_multi_open {
+        if !self.shell.panels.multi_open {
             let active = match side {
-                PanelSide::Left => self.active_left_panel,
-                PanelSide::Right => self.active_right_panel,
+                PanelSide::Left => self.shell.panels.active_left,
+                PanelSide::Right => self.shell.panels.active_right,
             };
             return active
                 .map(|item| item.persistence_id().to_string())
@@ -82,8 +86,8 @@ impl NyaTermApp {
         }
 
         let open = match side {
-            PanelSide::Left => &self.left_open_panels,
-            PanelSide::Right => &self.right_open_panels,
+            PanelSide::Left => &self.shell.panels.left_open,
+            PanelSide::Right => &self.shell.panels.right_open,
         };
         if open.is_empty() {
             return Vec::new();
@@ -95,7 +99,7 @@ impl NyaTermApp {
         };
         let mut ordered = Vec::new();
         for zone in zones {
-            for id in self.activity_bar_layout.zone(zone) {
+            for id in self.shell.chrome.activity_bar_layout.zone(zone) {
                 if open_set.contains(id) && Self::is_stackable_panel_id(id) {
                     ordered.push(id.clone());
                 }
@@ -105,27 +109,25 @@ impl NyaTermApp {
     }
 
     pub(in crate::features) fn side_overlay_panel(&self, side: PanelSide) -> Option<NavItem> {
-        if !self.panel_multi_open {
+        if !self.shell.panels.multi_open {
             return None;
         }
         let active = match side {
-            PanelSide::Left => self.active_left_panel,
-            PanelSide::Right => self.active_right_panel,
+            PanelSide::Left => self.shell.panels.active_left,
+            PanelSide::Right => self.shell.panels.active_right,
         }?;
         let id = active.persistence_id();
         Self::is_exclusive_panel_id(id).then_some(active)
     }
 
     pub(in crate::features) fn panel_stack_weight(&self, panel_id: &str) -> f32 {
-        self.panel_stack_sizes
-            .get(panel_id)
-            .copied()
-            .filter(|value| value.is_finite() && *value > 0.)
-            .unwrap_or(1.)
+        self.shell.panels.stack_weight(panel_id)
     }
 
     pub(in crate::features) fn panel_side_for_item(&self, item: NavItem) -> Option<PanelSide> {
-        self.activity_bar_layout
+        self.shell
+            .chrome
+            .activity_bar_layout
             .side_for_entry(item.persistence_id())
             .or_else(|| item.is_left_panel().then_some(PanelSide::Left))
             .or_else(|| item.is_right_panel().then_some(PanelSide::Right))
@@ -140,7 +142,7 @@ impl NyaTermApp {
             self.open_page(NavItem::Settings, cx);
             return;
         }
-        if !self.panel_multi_open {
+        if !self.shell.panels.multi_open {
             self.open_panel(item, cx);
             return;
         }
@@ -151,18 +153,18 @@ impl NyaTermApp {
             return;
         };
 
-        self.main_mode = MainMode::Workspace;
-        self.selected_nav = item;
+        self.shell.navigation.main_mode = MainMode::Workspace;
+        self.shell.navigation.selected_nav = item;
         if item == NavItem::Recording {
-            self.right_focus = RightFocus::Recording;
+            self.shell.panels.right_focus = RightFocus::Recording;
         } else {
-            self.right_focus = RightFocus::Default;
+            self.shell.panels.right_focus = RightFocus::Default;
         }
 
         if Self::is_exclusive_panel_id(&id) {
             let active = match side {
-                PanelSide::Left => self.active_left_panel,
-                PanelSide::Right => self.active_right_panel,
+                PanelSide::Left => self.shell.panels.active_left,
+                PanelSide::Right => self.shell.panels.active_right,
             };
             if active == Some(item) {
                 // Dismiss exclusive overlay to stack.
@@ -172,24 +174,24 @@ impl NyaTermApp {
                     .find_map(|open_id| NavItem::from_persistence_id(&open_id));
                 match side {
                     PanelSide::Left => {
-                        self.active_left_panel = fallback;
-                        self.left_sidebar_collapsed = fallback.is_none();
+                        self.shell.panels.active_left = fallback;
+                        self.shell.panels.left_collapsed = fallback.is_none();
                     }
                     PanelSide::Right => {
-                        self.active_right_panel = fallback;
-                        self.right_inspector_collapsed = fallback.is_none();
+                        self.shell.panels.active_right = fallback;
+                        self.shell.panels.right_collapsed = fallback.is_none();
                     }
                 }
                 self.terminal.view.status = format!("{} closed", item.label());
             } else {
                 match side {
                     PanelSide::Left => {
-                        self.active_left_panel = Some(item);
-                        self.left_sidebar_collapsed = false;
+                        self.shell.panels.active_left = Some(item);
+                        self.shell.panels.left_collapsed = false;
                     }
                     PanelSide::Right => {
-                        self.active_right_panel = Some(item);
-                        self.right_inspector_collapsed = false;
+                        self.shell.panels.active_right = Some(item);
+                        self.shell.panels.right_collapsed = false;
                     }
                 }
                 self.terminal.view.status = format!("{} opened", item.label());
@@ -200,13 +202,13 @@ impl NyaTermApp {
         }
 
         let open_list = match side {
-            PanelSide::Left => &mut self.left_open_panels,
-            PanelSide::Right => &mut self.right_open_panels,
+            PanelSide::Left => &mut self.shell.panels.left_open,
+            PanelSide::Right => &mut self.shell.panels.right_open,
         };
         let is_open = open_list.iter().any(|value| value == &id);
         let active = match side {
-            PanelSide::Left => self.active_left_panel,
-            PanelSide::Right => self.active_right_panel,
+            PanelSide::Left => self.shell.panels.active_left,
+            PanelSide::Right => self.shell.panels.active_right,
         };
 
         // If exclusive overlay is showing and stacked panel already open, reveal stack.
@@ -217,12 +219,12 @@ impl NyaTermApp {
         {
             match side {
                 PanelSide::Left => {
-                    self.active_left_panel = Some(item);
-                    self.left_sidebar_collapsed = false;
+                    self.shell.panels.active_left = Some(item);
+                    self.shell.panels.left_collapsed = false;
                 }
                 PanelSide::Right => {
-                    self.active_right_panel = Some(item);
-                    self.right_inspector_collapsed = false;
+                    self.shell.panels.active_right = Some(item);
+                    self.shell.panels.right_collapsed = false;
                 }
             }
             self.terminal.view.status = format!("{} focused", item.label());
@@ -247,14 +249,14 @@ impl NyaTermApp {
             };
             match side {
                 PanelSide::Left => {
-                    self.active_left_panel = next_active;
-                    self.left_sidebar_collapsed =
-                        next_active.is_none() && self.left_open_panels.is_empty();
+                    self.shell.panels.active_left = next_active;
+                    self.shell.panels.left_collapsed =
+                        next_active.is_none() && self.shell.panels.left_open.is_empty();
                 }
                 PanelSide::Right => {
-                    self.active_right_panel = next_active;
-                    self.right_inspector_collapsed =
-                        next_active.is_none() && self.right_open_panels.is_empty();
+                    self.shell.panels.active_right = next_active;
+                    self.shell.panels.right_collapsed =
+                        next_active.is_none() && self.shell.panels.right_open.is_empty();
                 }
             }
             self.terminal.view.status = format!("{} closed", item.label());
@@ -262,12 +264,12 @@ impl NyaTermApp {
             open_list.push(id);
             match side {
                 PanelSide::Left => {
-                    self.active_left_panel = Some(item);
-                    self.left_sidebar_collapsed = false;
+                    self.shell.panels.active_left = Some(item);
+                    self.shell.panels.left_collapsed = false;
                 }
                 PanelSide::Right => {
-                    self.active_right_panel = Some(item);
-                    self.right_inspector_collapsed = false;
+                    self.shell.panels.active_right = Some(item);
+                    self.shell.panels.right_collapsed = false;
                 }
             }
             self.terminal.view.status = format!("{} opened", item.label());
@@ -277,39 +279,45 @@ impl NyaTermApp {
     }
 
     pub(in crate::features) fn ensure_panel_in_stack(&mut self, item: NavItem) {
-        self.main_mode = MainMode::Workspace;
-        self.selected_nav = item;
-        if !self.panel_multi_open {
+        self.shell.navigation.main_mode = MainMode::Workspace;
+        self.shell.navigation.selected_nav = item;
+        if !self.shell.panels.multi_open {
             self.ensure_panel_open(item);
             return;
         }
         let id = item.persistence_id().to_string();
         match self.panel_side_for_item(item) {
             Some(PanelSide::Left) => {
-                self.left_sidebar_collapsed = false;
+                self.shell.panels.left_collapsed = false;
                 if Self::is_exclusive_panel_id(&id) {
-                    self.active_left_panel = Some(item);
+                    self.shell.panels.active_left = Some(item);
                 } else {
-                    if !self.left_open_panels.iter().any(|value| value == &id) {
-                        self.left_open_panels.push(id);
+                    if !self.shell.panels.left_open.iter().any(|value| value == &id) {
+                        self.shell.panels.left_open.push(id);
                     }
-                    self.active_left_panel = Some(item);
+                    self.shell.panels.active_left = Some(item);
                 }
             }
             Some(PanelSide::Right) => {
-                self.right_inspector_collapsed = false;
-                self.right_focus = if item == NavItem::Recording {
+                self.shell.panels.right_collapsed = false;
+                self.shell.panels.right_focus = if item == NavItem::Recording {
                     RightFocus::Recording
                 } else {
                     RightFocus::Default
                 };
                 if Self::is_exclusive_panel_id(&id) {
-                    self.active_right_panel = Some(item);
+                    self.shell.panels.active_right = Some(item);
                 } else {
-                    if !self.right_open_panels.iter().any(|value| value == &id) {
-                        self.right_open_panels.push(id);
+                    if !self
+                        .shell
+                        .panels
+                        .right_open
+                        .iter()
+                        .any(|value| value == &id)
+                    {
+                        self.shell.panels.right_open.push(id);
                     }
-                    self.active_right_panel = Some(item);
+                    self.shell.panels.active_right = Some(item);
                 }
             }
             None => {}
@@ -325,15 +333,13 @@ impl NyaTermApp {
         container_height: f32,
         cx: &mut Context<Self>,
     ) {
-        self.panel_stack_resize = Some(PanelStackResizeState {
+        self.shell.panels.start_stack_resize(
             side,
-            above_id: above_id.clone(),
-            below_id: below_id.clone(),
-            start_y: event.position.y,
-            above_weight: self.panel_stack_weight(&above_id),
-            below_weight: self.panel_stack_weight(&below_id),
-            container_height: container_height.max(1.),
-        });
+            above_id,
+            below_id,
+            event.position.y,
+            container_height,
+        );
         self.terminal.view.status = "resizing panel stack".to_string();
         cx.notify();
     }
@@ -343,24 +349,9 @@ impl NyaTermApp {
         event: &MouseMoveEvent,
         cx: &mut Context<Self>,
     ) {
-        let Some(state) = self.panel_stack_resize.clone() else {
-            return;
-        };
-        let delta_px = f32::from(event.position.y - state.start_y);
-        let pair = state.above_weight + state.below_weight;
-        if pair <= 0. || state.container_height <= 0. {
-            return;
+        if self.shell.panels.update_stack_resize(event.position.y) {
+            cx.notify();
         }
-        let px_per_weight = state.container_height / pair;
-        let min_weight = (48. / px_per_weight).min(pair / 2.).max(0.05);
-        let next_above =
-            (state.above_weight + delta_px / px_per_weight).clamp(min_weight, pair - min_weight);
-        let next_below = pair - next_above;
-        self.panel_stack_sizes
-            .insert(state.above_id.clone(), next_above);
-        self.panel_stack_sizes
-            .insert(state.below_id.clone(), next_below);
-        cx.notify();
     }
 
     pub(in crate::features) fn finish_panel_stack_resize(
@@ -368,7 +359,7 @@ impl NyaTermApp {
         _event: &MouseUpEvent,
         cx: &mut Context<Self>,
     ) {
-        if self.panel_stack_resize.take().is_some() {
+        if self.shell.panels.finish_stack_resize() {
             self.persist_ui_layout();
             self.terminal.view.status = "panel stack sizes saved".to_string();
             cx.notify();
@@ -376,11 +367,13 @@ impl NyaTermApp {
     }
 
     pub(in crate::features) fn sync_panel_stack_to_settings(&mut self) {
-        self.settings.ui_panel_multi_open = self.panel_multi_open;
-        self.settings.ui_left_open_panels = self.left_open_panels.clone();
-        self.settings.ui_right_open_panels = self.right_open_panels.clone();
+        self.settings.ui_panel_multi_open = self.shell.panels.multi_open;
+        self.settings.ui_left_open_panels = self.shell.panels.left_open.clone();
+        self.settings.ui_right_open_panels = self.shell.panels.right_open.clone();
         self.settings.ui_panel_stack_sizes = self
-            .panel_stack_sizes
+            .shell
+            .panels
+            .stack_sizes
             .iter()
             .filter_map(|(key, value)| {
                 let scaled = (*value * 1000.).round();
@@ -390,29 +383,29 @@ impl NyaTermApp {
     }
 
     pub(in crate::features) fn apply_panel_stack_from_settings(&mut self) {
-        self.panel_multi_open = self.settings.ui_panel_multi_open;
-        self.left_open_panels = self.settings.ui_left_open_panels.clone();
-        self.right_open_panels = self.settings.ui_right_open_panels.clone();
-        self.panel_stack_sizes = self
+        self.shell.panels.multi_open = self.settings.ui_panel_multi_open;
+        self.shell.panels.left_open = self.settings.ui_left_open_panels.clone();
+        self.shell.panels.right_open = self.settings.ui_right_open_panels.clone();
+        self.shell.panels.stack_sizes = self
             .settings
             .ui_panel_stack_sizes
             .iter()
             .filter_map(|(key, value)| (*value > 0).then(|| (key.clone(), (*value as f32) / 1000.)))
             .collect();
-        if self.panel_multi_open {
-            if self.left_open_panels.is_empty() {
-                if let Some(panel) = self.active_left_panel {
+        if self.shell.panels.multi_open {
+            if self.shell.panels.left_open.is_empty() {
+                if let Some(panel) = self.shell.panels.active_left {
                     let id = panel.persistence_id().to_string();
                     if Self::is_stackable_panel_id(&id) {
-                        self.left_open_panels.push(id);
+                        self.shell.panels.left_open.push(id);
                     }
                 }
             }
-            if self.right_open_panels.is_empty() {
-                if let Some(panel) = self.active_right_panel {
+            if self.shell.panels.right_open.is_empty() {
+                if let Some(panel) = self.shell.panels.active_right {
                     let id = panel.persistence_id().to_string();
                     if Self::is_stackable_panel_id(&id) {
-                        self.right_open_panels.push(id);
+                        self.shell.panels.right_open.push(id);
                     }
                 }
             }
@@ -433,14 +426,24 @@ impl NyaTermApp {
                 PanelSide::Left => self.current_left_panel(),
                 PanelSide::Right => self.current_right_panel(),
             }
-            .or_else(|| self.activity_bar_layout.first_panel_on_side(side))
+            .or_else(|| {
+                self.shell
+                    .chrome
+                    .activity_bar_layout
+                    .first_panel_on_side(side)
+            })
             .unwrap_or(NavItem::Workspace);
             self.single_side_panel(side, fallback, window, cx)
-        } else if open_ids.len() == 1 || !self.panel_multi_open {
+        } else if open_ids.len() == 1 || !self.shell.panels.multi_open {
             let panel = open_ids
                 .first()
                 .and_then(|id| NavItem::from_persistence_id(id))
-                .or_else(|| self.activity_bar_layout.first_panel_on_side(side))
+                .or_else(|| {
+                    self.shell
+                        .chrome
+                        .activity_bar_layout
+                        .first_panel_on_side(side)
+                })
                 .unwrap_or(NavItem::Workspace);
             self.single_side_panel(side, panel, window, cx)
         } else {
@@ -701,7 +704,7 @@ impl NyaTermApp {
                             cx.listener(|this, _, _, cx| {
                                 this.ai.history.open = false;
                                 this.ai.panel.execution_menu_open = false;
-                                this.settings_active_tab = SettingsTab::AiGeneral;
+                                this.shell.navigation.settings.active_tab = SettingsTab::AiGeneral;
                                 this.open_page(NavItem::Settings, cx);
                             }),
                         ))

crates/nyaterm-desktop/src/features/shell/state.rs

@@ -4,12 +4,44 @@
 //! lifecycles that span those views so the composition root does not retain
 //! independently mutable mirrors.
 
-use gpui::Pixels;
+use std::collections::{HashMap, HashSet};
+use std::time::{Duration, Instant};
 
-use crate::models::{BottomPanelMode, BottomPanelResizeState};
+use gpui::{Pixels, ScrollHandle, WindowHandle};
+
+use super::super::app_state::SettingsDraftSnapshot;
+use super::super::settings_window::SettingsWindow;
+use crate::models::{
+    ActivityBarContextMenuState, ActivityBarLayoutState, BottomPanelMode, BottomPanelResizeState,
+    HeaderStatusState, MainMode, NavItem, PanelResizeSide, PanelResizeState, PanelSide,
+    PanelStackResizeState, RightFocus, SettingsTab, TitleMenu, TitleMenuSubmenu, WorkspacePaneNode,
+    WorkspaceSplitResizeState, WorkspaceSplitState,
+};
 
 pub(in crate::features) struct ShellFeatureState {
     pub bottom_panel: ShellBottomPanelState,
+    pub viewport: ShellViewportState,
+    pub navigation: ShellNavigationState,
+    pub panels: ShellPanelState,
+    pub chrome: ShellChromeState,
+    pub workspace: ShellWorkspaceState,
+}
+
+pub(in crate::features) struct ShellFeatureInit {
+    pub bottom_panel_mode: BottomPanelMode,
+    pub quick_commands_height: f32,
+    pub command_send_height: f32,
+    pub active_left_panel: Option<NavItem>,
+    pub active_right_panel: Option<NavItem>,
+    pub left_open_panels: Vec<String>,
+    pub right_open_panels: Vec<String>,
+    pub panel_stack_sizes: HashMap<String, f32>,
+    pub panel_multi_open: bool,
+    pub left_sidebar_collapsed: bool,
+    pub right_inspector_collapsed: bool,
+    pub left_panel_width: f32,
+    pub right_panel_width: f32,
+    pub activity_bar_layout: ActivityBarLayoutState,
 }
 
 pub(in crate::features) struct ShellBottomPanelState {
@@ -19,19 +51,145 @@ pub(in crate::features) struct ShellBottomPanelState {
     pub resize: Option<BottomPanelResizeState>,
 }
 
+/// Window geometry and viewport-derived caches.
+pub(in crate::features) struct ShellViewportState {
+    pub size: (f32, f32),
+    pub wallpaper_tile_dimensions: Option<(String, u32, u32)>,
+    pub last_change_at: Option<Instant>,
+    pub title_drag_active_until: Option<Instant>,
+}
+
+/// Top-level page navigation and the settings-page/window lifecycle.
+pub(in crate::features) struct ShellNavigationState {
+    pub selected_nav: NavItem,
+    pub main_mode: MainMode,
+    pub settings: ShellSettingsNavigationState,
+}
+
+pub(in crate::features) struct ShellSettingsNavigationState {
+    pub active_tab: SettingsTab,
+    pub expanded_groups: HashSet<String>,
+    pub draft_snapshot: Option<SettingsDraftSnapshot>,
+    pub window: Option<WindowHandle<SettingsWindow>>,
+    pub window_open_pending: bool,
+    pub previous_left_collapsed: Option<bool>,
+    pub previous_right_collapsed: Option<bool>,
+}
+
+/// Side-panel selection, stack layout and resize interaction state.
+pub(in crate::features) struct ShellPanelState {
+    pub active_left: Option<NavItem>,
+    pub active_right: Option<NavItem>,
+    pub left_open: Vec<String>,
+    pub right_open: Vec<String>,
+    pub stack_sizes: HashMap<String, f32>,
+    pub multi_open: bool,
+    pub right_focus: RightFocus,
+    pub left_collapsed: bool,
+    pub right_collapsed: bool,
+    pub mobile_left_open: bool,
+    pub mobile_right_open: bool,
+    pub left_width: f32,
+    pub right_width: f32,
+    pub resize: Option<PanelResizeState>,
+    pub stack_resize: Option<PanelStackResizeState>,
+}
+
+/// Activity bar, title menus, tab-strip menus and connection-failure chrome.
+pub(in crate::features) struct ShellChromeState {
+    pub activity_bar_layout: ActivityBarLayoutState,
+    pub activity_bar_context_menu: Option<ActivityBarContextMenuState>,
+    pub title_menu_open: Option<TitleMenu>,
+    pub title_menu_submenu: Option<TitleMenuSubmenu>,
+    pub header_status: HeaderStatusState,
+    pub open_tabs_menu_open: bool,
+    pub new_session_menu_open: bool,
+    pub new_session_all_sessions_open: bool,
+    pub new_session_group_menu_path: Vec<String>,
+    pub session_tab_strip_scroll: ScrollHandle,
+    pub session_tab_scroll_into_view_pending: bool,
+    pub last_connect_failure_name: Option<String>,
+    pub last_connect_failure_error: Option<String>,
+}
+
+/// Global and per-tab pane trees for the workspace surface.
+pub(in crate::features) struct ShellWorkspaceState {
+    pub split: Option<WorkspaceSplitState>,
+    pub split_resize: Option<WorkspaceSplitResizeState>,
+    pub pane_roots: HashMap<String, WorkspacePaneNode>,
+    pub tab_owner: HashMap<String, String>,
+    pub focused_terminal_leaf_id: Option<String>,
+    pub pane_layout_restored: bool,
+}
+
 impl ShellFeatureState {
-    pub(in crate::features) fn new(
-        bottom_panel_mode: BottomPanelMode,
-        quick_commands_height: f32,
-        command_send_height: f32,
-    ) -> Self {
+    pub(in crate::features) fn new(init: ShellFeatureInit) -> Self {
         Self {
             bottom_panel: ShellBottomPanelState {
-                mode: bottom_panel_mode,
-                quick_commands_height,
-                command_send_height,
+                mode: init.bottom_panel_mode,
+                quick_commands_height: init.quick_commands_height,
+                command_send_height: init.command_send_height,
                 resize: None,
             },
+            viewport: ShellViewportState {
+                size: (1280., 800.),
+                wallpaper_tile_dimensions: None,
+                last_change_at: None,
+                title_drag_active_until: None,
+            },
+            navigation: ShellNavigationState {
+                selected_nav: NavItem::Workspace,
+                main_mode: MainMode::Workspace,
+                settings: ShellSettingsNavigationState {
+                    active_tab: SettingsTab::General,
+                    expanded_groups: HashSet::from(["workspace".to_string()]),
+                    draft_snapshot: None,
+                    window: None,
+                    window_open_pending: false,
+                    previous_left_collapsed: None,
+                    previous_right_collapsed: None,
+                },
+            },
+            panels: ShellPanelState {
+                active_left: init.active_left_panel,
+                active_right: init.active_right_panel,
+                left_open: init.left_open_panels,
+                right_open: init.right_open_panels,
+                stack_sizes: init.panel_stack_sizes,
+                multi_open: init.panel_multi_open,
+                right_focus: RightFocus::Default,
+                left_collapsed: init.left_sidebar_collapsed,
+                right_collapsed: init.right_inspector_collapsed,
+                mobile_left_open: false,
+                mobile_right_open: false,
+                left_width: init.left_panel_width,
+                right_width: init.right_panel_width,
+                resize: None,
+                stack_resize: None,
+            },
+            chrome: ShellChromeState {
+                activity_bar_layout: init.activity_bar_layout,
+                activity_bar_context_menu: None,
+                title_menu_open: None,
+                title_menu_submenu: None,
+                header_status: HeaderStatusState::default(),
+                open_tabs_menu_open: false,
+                new_session_menu_open: false,
+                new_session_all_sessions_open: false,
+                new_session_group_menu_path: Vec::new(),
+                session_tab_strip_scroll: ScrollHandle::new(),
+                session_tab_scroll_into_view_pending: false,
+                last_connect_failure_name: None,
+                last_connect_failure_error: None,
+            },
+            workspace: ShellWorkspaceState {
+                split: None,
+                split_resize: None,
+                pane_roots: HashMap::new(),
+                tab_owner: HashMap::new(),
+                focused_terminal_leaf_id: None,
+                pane_layout_restored: false,
+            },
         }
     }
 }
@@ -77,16 +235,225 @@ impl ShellBottomPanelState {
     }
 }
 
+impl ShellViewportState {
+    pub(in crate::features) fn update_size(&mut self, size: (f32, f32), now: Instant) -> bool {
+        if self.size == size {
+            return false;
+        }
+        self.size = size;
+        self.last_change_at = Some(now);
+        true
+    }
+
+    pub(in crate::features) fn mark_title_drag(&mut self, now: Instant, hold: Duration) {
+        self.title_drag_active_until = Some(now + hold);
+    }
+
+    pub(in crate::features) fn title_drag_active(&self, now: Instant) -> bool {
+        self.title_drag_active_until
+            .is_some_and(|until| now < until)
+    }
+}
+
+impl ShellPanelState {
+    const LEFT_WIDTH_MIN: f32 = 160.;
+    const LEFT_WIDTH_MAX: f32 = 720.;
+    const RIGHT_WIDTH_MIN: f32 = 200.;
+    const RIGHT_WIDTH_MAX: f32 = 720.;
+
+    pub(in crate::features) fn start_resize(&mut self, side: PanelResizeSide, start_x: Pixels) {
+        let start_width = match side {
+            PanelResizeSide::Left => self.left_width,
+            PanelResizeSide::Right => self.right_width,
+        };
+        self.resize = Some(PanelResizeState {
+            side,
+            start_x,
+            start_width: gpui::px(start_width),
+        });
+    }
+
+    pub(in crate::features) fn update_resize(
+        &mut self,
+        current_x: Pixels,
+    ) -> Option<(PanelResizeSide, f32)> {
+        let state = self.resize?;
+        let delta = f32::from(current_x - state.start_x);
+        let start = f32::from(state.start_width);
+        let width = match state.side {
+            PanelResizeSide::Left => {
+                self.left_width = (start + delta).clamp(Self::LEFT_WIDTH_MIN, Self::LEFT_WIDTH_MAX);
+                self.left_width
+            }
+            PanelResizeSide::Right => {
+                self.right_width =
+                    (start - delta).clamp(Self::RIGHT_WIDTH_MIN, Self::RIGHT_WIDTH_MAX);
+                self.right_width
+            }
+        };
+        Some((state.side, width))
+    }
+
+    pub(in crate::features) fn finish_resize(&mut self) -> bool {
+        self.resize.take().is_some()
+    }
+
+    pub(in crate::features) fn stack_weight(&self, panel_id: &str) -> f32 {
+        self.stack_sizes
+            .get(panel_id)
+            .copied()
+            .filter(|value| value.is_finite() && *value > 0.)
+            .unwrap_or(1.)
+    }
+
+    pub(in crate::features) fn start_stack_resize(
+        &mut self,
+        side: PanelSide,
+        above_id: String,
+        below_id: String,
+        start_y: Pixels,
+        container_height: f32,
+    ) {
+        self.stack_resize = Some(PanelStackResizeState {
+            side,
+            above_weight: self.stack_weight(&above_id),
+            below_weight: self.stack_weight(&below_id),
+            above_id,
+            below_id,
+            start_y,
+            container_height: container_height.max(1.),
+        });
+    }
+
+    pub(in crate::features) fn update_stack_resize(&mut self, current_y: Pixels) -> bool {
+        let Some(state) = self.stack_resize.as_ref() else {
+            return false;
+        };
+        let delta_px = f32::from(current_y - state.start_y);
+        let pair = state.above_weight + state.below_weight;
+        if pair <= 0. || state.container_height <= 0. {
+            return false;
+        }
+        let px_per_weight = state.container_height / pair;
+        let min_weight = (48. / px_per_weight).min(pair / 2.).max(0.05);
+        let next_above =
+            (state.above_weight + delta_px / px_per_weight).clamp(min_weight, pair - min_weight);
+        let next_below = pair - next_above;
+        self.stack_sizes.insert(state.above_id.clone(), next_above);
+        self.stack_sizes.insert(state.below_id.clone(), next_below);
+        true
+    }
+
+    pub(in crate::features) fn finish_stack_resize(&mut self) -> bool {
+        self.stack_resize.take().is_some()
+    }
+}
+
+impl ShellChromeState {
+    pub(in crate::features) fn prepare_session_switch(&mut self) {
+        self.open_tabs_menu_open = false;
+        self.close_new_session_menu();
+        self.session_tab_scroll_into_view_pending = true;
+    }
+
+    pub(in crate::features) fn toggle_open_tabs_menu(&mut self) {
+        self.open_tabs_menu_open = !self.open_tabs_menu_open;
+        if self.open_tabs_menu_open {
+            self.close_new_session_menu();
+            self.title_menu_open = None;
+        }
+    }
+
+    pub(in crate::features) fn close_open_tabs_menu(&mut self) -> bool {
+        std::mem::take(&mut self.open_tabs_menu_open)
+    }
+
+    pub(in crate::features) fn toggle_new_session_menu(&mut self) {
+        self.new_session_menu_open = !self.new_session_menu_open;
+        if self.new_session_menu_open {
+            self.open_tabs_menu_open = false;
+            self.title_menu_open = None;
+        }
+        self.new_session_all_sessions_open = false;
+        self.new_session_group_menu_path.clear();
+    }
+
+    pub(in crate::features) fn close_new_session_menu(&mut self) -> bool {
+        let changed = self.new_session_menu_open
+            || self.new_session_all_sessions_open
+            || !self.new_session_group_menu_path.is_empty();
+        self.new_session_menu_open = false;
+        self.new_session_all_sessions_open = false;
+        self.new_session_group_menu_path.clear();
+        changed
+    }
+}
+
+impl ShellWorkspaceState {
+    pub(in crate::features) fn rebuild_tab_owners(&mut self) {
+        let mut owners = HashMap::new();
+        for (tab_root, tree) in &self.pane_roots {
+            for leaf in tree.session_ids() {
+                owners.insert(leaf, tab_root.clone());
+            }
+        }
+        self.tab_owner = owners;
+    }
+
+    pub(in crate::features) fn replace_session_id(&mut self, old_id: &str, new_id: &str) {
+        for root in self.pane_roots.values_mut() {
+            root.replace_session_id(old_id, new_id);
+        }
+        if let Some(root) = self.pane_roots.remove(old_id) {
+            self.pane_roots.insert(new_id.to_string(), root);
+        }
+        if let Some(root) = self.split.as_mut() {
+            root.replace_session_id(old_id, new_id);
+        }
+        self.rebuild_tab_owners();
+    }
+
+    pub(in crate::features) fn remove_session(&mut self, session_id: &str) {
+        self.tab_owner.remove(session_id);
+        self.pane_roots.remove(session_id);
+    }
+}
+
 #[cfg(test)]
 mod tests {
+    use std::collections::HashMap;
+    use std::time::{Duration, Instant};
+
     use gpui::px;
 
-    use super::ShellFeatureState;
-    use crate::models::BottomPanelMode;
+    use super::{ShellFeatureInit, ShellFeatureState};
+    use crate::models::{
+        ActivityBarLayoutState, BottomPanelMode, PanelResizeSide, PanelSide, WorkspacePaneNode,
+        WorkspaceSplitDirection,
+    };
+
+    fn shell(mode: BottomPanelMode) -> ShellFeatureState {
+        ShellFeatureState::new(ShellFeatureInit {
+            bottom_panel_mode: mode,
+            quick_commands_height: 120.,
+            command_send_height: 180.,
+            active_left_panel: None,
+            active_right_panel: None,
+            left_open_panels: Vec::new(),
+            right_open_panels: Vec::new(),
+            panel_stack_sizes: HashMap::new(),
+            panel_multi_open: false,
+            left_sidebar_collapsed: true,
+            right_inspector_collapsed: true,
+            left_panel_width: 240.,
+            right_panel_width: 320.,
+            activity_bar_layout: ActivityBarLayoutState::default(),
+        })
+    }
 
     #[test]
     fn bottom_panel_resize_updates_only_the_mode_that_started_the_drag() {
-        let mut shell = ShellFeatureState::new(BottomPanelMode::QuickCommands, 120., 180.);
+        let mut shell = shell(BottomPanelMode::QuickCommands);
 
         assert!(shell.bottom_panel.start_resize(px(400.)));
         shell.bottom_panel.mode = BottomPanelMode::CommandSend;
@@ -99,9 +466,109 @@ mod tests {
 
     #[test]
     fn hidden_bottom_panel_does_not_start_resize() {
-        let mut shell = ShellFeatureState::new(BottomPanelMode::Hidden, 120., 180.);
+        let mut shell = shell(BottomPanelMode::Hidden);
 
         assert!(!shell.bottom_panel.start_resize(px(400.)));
         assert!(shell.bottom_panel.resize.is_none());
     }
+
+    #[test]
+    fn panel_resize_clamps_each_side_and_finishes_once() {
+        let mut shell = shell(BottomPanelMode::Hidden);
+
+        shell.panels.start_resize(PanelResizeSide::Left, px(100.));
+        assert_eq!(
+            shell.panels.update_resize(px(-100.)),
+            Some((PanelResizeSide::Left, 160.))
+        );
+        assert!(shell.panels.finish_resize());
+        assert!(!shell.panels.finish_resize());
+
+        shell.panels.start_resize(PanelResizeSide::Right, px(100.));
+        assert_eq!(
+            shell.panels.update_resize(px(-500.)),
+            Some((PanelResizeSide::Right, 720.))
+        );
+    }
+
+    #[test]
+    fn panel_stack_resize_preserves_pair_weight() {
+        let mut shell = shell(BottomPanelMode::Hidden);
+        shell.panels.stack_sizes.insert("above".to_string(), 2.);
+        shell.panels.stack_sizes.insert("below".to_string(), 1.);
+        shell.panels.start_stack_resize(
+            PanelSide::Left,
+            "above".to_string(),
+            "below".to_string(),
+            px(100.),
+            300.,
+        );
+
+        assert!(shell.panels.update_stack_resize(px(150.)));
+        let total = shell.panels.stack_sizes["above"] + shell.panels.stack_sizes["below"];
+        assert!((total - 3.).abs() < f32::EPSILON);
+        assert!(shell.panels.finish_stack_resize());
+    }
+
+    #[test]
+    fn chrome_menu_transitions_are_mutually_exclusive() {
+        let mut shell = shell(BottomPanelMode::Hidden);
+        shell.chrome.new_session_menu_open = true;
+        shell.chrome.new_session_all_sessions_open = true;
+        shell
+            .chrome
+            .new_session_group_menu_path
+            .push("group".to_string());
+
+        shell.chrome.toggle_open_tabs_menu();
+        assert!(shell.chrome.open_tabs_menu_open);
+        assert!(!shell.chrome.new_session_menu_open);
+        assert!(!shell.chrome.new_session_all_sessions_open);
+        assert!(shell.chrome.new_session_group_menu_path.is_empty());
+
+        shell.chrome.toggle_new_session_menu();
+        assert!(!shell.chrome.open_tabs_menu_open);
+        assert!(shell.chrome.new_session_menu_open);
+    }
+
+    #[test]
+    fn viewport_tracks_only_real_geometry_changes_and_title_drag_deadline() {
+        let mut shell = shell(BottomPanelMode::Hidden);
+        let now = Instant::now();
+        assert!(!shell.viewport.update_size((1280., 800.), now));
+        assert!(shell.viewport.update_size((1024., 768.), now));
+        assert_eq!(shell.viewport.last_change_at, Some(now));
+
+        shell
+            .viewport
+            .mark_title_drag(now, Duration::from_millis(10));
+        assert!(shell.viewport.title_drag_active(now));
+        assert!(
+            !shell
+                .viewport
+                .title_drag_active(now + Duration::from_millis(10))
+        );
+    }
+
+    #[test]
+    fn workspace_rebuilds_and_renames_tab_ownership() {
+        let mut shell = shell(BottomPanelMode::Hidden);
+        shell.workspace.pane_roots.insert(
+            "root".to_string(),
+            WorkspacePaneNode::Split {
+                id: "split".to_string(),
+                direction: WorkspaceSplitDirection::Vertical,
+                ratio_percent: 50,
+                first: Box::new(WorkspacePaneNode::leaf("root".to_string())),
+                second: Box::new(WorkspacePaneNode::leaf("leaf".to_string())),
+            },
+        );
+        shell.workspace.rebuild_tab_owners();
+        assert_eq!(shell.workspace.tab_owner["leaf"], "root");
+
+        shell.workspace.replace_session_id("root", "renamed");
+        assert!(shell.workspace.pane_roots.contains_key("renamed"));
+        assert_eq!(shell.workspace.tab_owner["leaf"], "renamed");
+        assert_eq!(shell.workspace.tab_owner["renamed"], "renamed");
+    }
 }

crates/nyaterm-desktop/src/features/shell/tab_windows_runtime.rs

@@ -25,7 +25,7 @@ impl NyaTermApp {
             .collect::<Vec<_>>();
         if live_ids.is_empty() {
             self.terminal.windows.tree = None;
-            self.focused_terminal_window_leaf_id = None;
+            self.shell.workspace.focused_terminal_leaf_id = None;
             return;
         }
 
@@ -44,7 +44,7 @@ impl NyaTermApp {
         }
 
         if let Some(root) = self.terminal.windows.tree.as_mut() {
-            let preferred = self.focused_terminal_window_leaf_id.clone();
+            let preferred = self.shell.workspace.focused_terminal_leaf_id.clone();
             for tab_id in &live_ids {
                 root.ensure_tab(tab_id, preferred.as_deref());
             }
@@ -52,11 +52,13 @@ impl NyaTermApp {
                 let _ = root.set_active_tab(&active);
             }
             if self
-                .focused_terminal_window_leaf_id
+                .shell
+                .workspace
+                .focused_terminal_leaf_id
                 .as_ref()
                 .is_none_or(|id| !root.leaf_ids().iter().any(|leaf| leaf == id))
             {
-                self.focused_terminal_window_leaf_id = root.first_leaf_id();
+                self.shell.workspace.focused_terminal_leaf_id = root.first_leaf_id();
             }
         }
     }
@@ -75,7 +77,7 @@ impl NyaTermApp {
         }
         let active = self.session.active_id.clone();
         let root = TerminalWindowNode::leaf(tab_ids, active);
-        self.focused_terminal_window_leaf_id = root.first_leaf_id();
+        self.shell.workspace.focused_terminal_leaf_id = root.first_leaf_id();
         self.terminal.windows.tree = Some(root);
     }
 
@@ -90,10 +92,10 @@ impl NyaTermApp {
             let _ = set_leaf_active(root, &leaf_id, &session_id);
             let _ = root.set_active_tab(&session_id);
         }
-        self.focused_terminal_window_leaf_id = Some(leaf_id);
+        self.shell.workspace.focused_terminal_leaf_id = Some(leaf_id);
         self.activate_session_id_with_surface_sync(&session_id, cx);
-        self.selected_nav = NavItem::Workspace;
-        self.main_mode = MainMode::Workspace;
+        self.shell.navigation.selected_nav = NavItem::Workspace;
+        self.shell.navigation.main_mode = MainMode::Workspace;
         cx.notify();
     }
 
@@ -115,7 +117,7 @@ impl NyaTermApp {
         };
         let _ = root.set_active_tab(&tab_id);
         if let Some(leaf_id) = find_leaf_with_tab(root, &tab_id) {
-            self.focused_terminal_window_leaf_id = Some(leaf_id);
+            self.shell.workspace.focused_terminal_leaf_id = Some(leaf_id);
         }
     }
 
@@ -131,7 +133,7 @@ impl NyaTermApp {
         };
         if root.place_tab_before(&tab_id, &before_tab_id) {
             let _ = root.set_active_tab(&tab_id);
-            self.focused_terminal_window_leaf_id =
+            self.shell.workspace.focused_terminal_leaf_id =
                 find_leaf_with_tab(root, &tab_id).or_else(|| root.first_leaf_id());
             self.activate_session_id_with_surface_sync(&tab_id, cx);
             self.terminal.view.status = format!(
@@ -188,11 +190,11 @@ impl NyaTermApp {
             return;
         }
         let _ = root.set_active_tab(&tab_id);
-        self.focused_terminal_window_leaf_id =
+        self.shell.workspace.focused_terminal_leaf_id =
             find_leaf_with_tab(root, &tab_id).or_else(|| root.first_leaf_id());
         self.activate_session_id_with_surface_sync(&tab_id, cx);
-        self.selected_nav = NavItem::Workspace;
-        self.main_mode = MainMode::Workspace;
+        self.shell.navigation.selected_nav = NavItem::Workspace;
+        self.shell.navigation.main_mode = MainMode::Workspace;
         let zone_label = match zone {
             TabDockZone::Center => "merged into leaf".to_string(),
             TabDockZone::Edge(edge) => format!("split to {}", edge.label()),
@@ -224,20 +226,20 @@ impl NyaTermApp {
             return;
         };
         // Clear global pane splits so multi-leaf rendering takes precedence cleanly.
-        self.workspace_split = None;
-        self.workspace_split_resize = None;
+        self.shell.workspace.split = None;
+        self.shell.workspace.split_resize = None;
         if let Some(active) = self.session.active_id.clone() {
             let mut root = layout;
             let _ = root.set_active_tab(&active);
-            self.focused_terminal_window_leaf_id =
+            self.shell.workspace.focused_terminal_leaf_id =
                 find_leaf_with_tab(&root, &active).or_else(|| root.first_leaf_id());
             self.terminal.windows.tree = Some(root);
         } else {
-            self.focused_terminal_window_leaf_id = layout.first_leaf_id();
+            self.shell.workspace.focused_terminal_leaf_id = layout.first_leaf_id();
             self.terminal.windows.tree = Some(layout);
         }
-        self.selected_nav = NavItem::Workspace;
-        self.main_mode = MainMode::Workspace;
+        self.shell.navigation.selected_nav = NavItem::Workspace;
+        self.shell.navigation.main_mode = MainMode::Workspace;
         self.terminal.view.status = format!("applied {}", mode.label().to_ascii_lowercase());
         self.persist_terminal_window_layout();
         // Global pane layout is obsolete while multi-leaf is active.
@@ -296,11 +298,11 @@ impl NyaTermApp {
         if !matches!(restored, TerminalWindowNode::Split { .. }) {
             return;
         }
-        self.focused_terminal_window_leaf_id = restored.first_leaf_id();
+        self.shell.workspace.focused_terminal_leaf_id = restored.first_leaf_id();
         if let Some(active) = self.session.active_id.clone() {
             let mut root = restored;
             let _ = root.set_active_tab(&active);
-            self.focused_terminal_window_leaf_id =
+            self.shell.workspace.focused_terminal_leaf_id =
                 find_leaf_with_tab(&root, &active).or_else(|| root.first_leaf_id());
             self.terminal.windows.tree = Some(root);
         } else {

crates/nyaterm-desktop/src/features/shell/workspace_runtime.rs

@@ -23,10 +23,10 @@ impl NyaTermApp {
 
     pub(in crate::features) fn prune_workspace_split(&mut self) {
         let live_ids = self.live_session_ids_with_disconnected();
-        let before_roots = self.session_pane_roots.clone();
-        let root_keys: Vec<String> = self.session_pane_roots.keys().cloned().collect();
+        let before_roots = self.shell.workspace.pane_roots.clone();
+        let root_keys: Vec<String> = self.shell.workspace.pane_roots.keys().cloned().collect();
         for tab_root in root_keys {
-            let Some(root) = self.session_pane_roots.remove(&tab_root) else {
+            let Some(root) = self.shell.workspace.pane_roots.remove(&tab_root) else {
                 continue;
             };
             match root.prune(&live_ids) {
@@ -41,7 +41,7 @@ impl NyaTermApp {
                                 .next()
                                 .unwrap_or_else(|| tab_root.clone())
                         };
-                        self.session_pane_roots.insert(key, node);
+                        self.shell.workspace.pane_roots.insert(key, node);
                     }
                     // Single leaf collapses to no stored tree for this tab.
                 }
@@ -49,13 +49,13 @@ impl NyaTermApp {
             }
         }
         // Also prune legacy workspace_split if roots empty (migration path).
-        if self.session_pane_roots.is_empty() {
-            if let Some(root) = self.workspace_split.take() {
+        if self.shell.workspace.pane_roots.is_empty() {
+            if let Some(root) = self.shell.workspace.split.take() {
                 match root.prune(&live_ids) {
                     Some(node) => {
                         if node.is_split() {
                             if let Some(first) = node.session_ids().into_iter().next() {
-                                self.session_pane_roots.insert(first.clone(), node);
+                                self.shell.workspace.pane_roots.insert(first.clone(), node);
                             }
                         } else if let WorkspacePaneNode::Leaf { session_id } = node {
                             if self.session.active_id.is_none() {
@@ -69,7 +69,7 @@ impl NyaTermApp {
         }
         self.rebuild_session_tab_owners();
         self.sync_workspace_split_from_active_tab();
-        if self.session_pane_roots != before_roots {
+        if self.shell.workspace.pane_roots != before_roots {
             self.persist_workspace_pane_layout();
             if self.startup_restore_complete {
                 self.persist_open_tabs();
@@ -89,29 +89,21 @@ impl NyaTermApp {
 
     /// Rebuild leaf→tab-root ownership from `session_pane_roots`.
     pub(in crate::features) fn rebuild_session_tab_owners(&mut self) {
-        self.session_tab_owner.clear();
-        let roots: Vec<(String, WorkspacePaneNode)> = self
-            .session_pane_roots
-            .iter()
-            .map(|(k, v)| (k.clone(), v.clone()))
-            .collect();
-        for (tab_root, tree) in roots {
-            for leaf in tree.session_ids() {
-                self.session_tab_owner.insert(leaf, tab_root.clone());
-            }
-        }
+        self.shell.workspace.rebuild_tab_owners();
     }
 
     /// Expose the active tab's pane tree via `workspace_split` for existing renderers.
     pub(in crate::features) fn sync_workspace_split_from_active_tab(&mut self) {
         let Some(active) = self.session.active_id.clone() else {
-            self.workspace_split = None;
+            self.shell.workspace.split = None;
             self.sync_terminal_frame_snapshot_priority();
             return;
         };
         let tab_root = self.tab_root_for_session(&active);
-        self.workspace_split = self
-            .session_pane_roots
+        self.shell.workspace.split = self
+            .shell
+            .workspace
+            .pane_roots
             .get(&tab_root)
             .filter(|root| root.is_split())
             .cloned();
@@ -123,9 +115,9 @@ impl NyaTermApp {
             return;
         };
         let tab_root = self.tab_root_for_session(&active);
-        if let Some(root) = self.workspace_split.clone() {
+        if let Some(root) = self.shell.workspace.split.clone() {
             if root.is_split() {
-                self.session_pane_roots.insert(tab_root, root);
+                self.shell.workspace.pane_roots.insert(tab_root, root);
                 self.rebuild_session_tab_owners();
             }
         }
@@ -139,7 +131,7 @@ impl NyaTermApp {
     ) {
         let split_id = uuid();
         let tab_root = self.tab_root_for_session(&primary_session_id);
-        if let Some(root) = self.session_pane_roots.get_mut(&tab_root) {
+        if let Some(root) = self.shell.workspace.pane_roots.get_mut(&tab_root) {
             if root.split_leaf(
                 &primary_session_id,
                 secondary_session_id.clone(),
@@ -149,8 +141,8 @@ impl NyaTermApp {
                 self.rebuild_session_tab_owners();
                 self.activate_session_id(&secondary_session_id);
                 self.sync_workspace_split_from_active_tab();
-                self.selected_nav = NavItem::Workspace;
-                self.main_mode = MainMode::Workspace;
+                self.shell.navigation.selected_nav = NavItem::Workspace;
+                self.shell.navigation.main_mode = MainMode::Workspace;
                 self.persist_workspace_pane_layout();
                 if self.startup_restore_complete {
                     self.persist_open_tabs();
@@ -166,12 +158,12 @@ impl NyaTermApp {
             first: Box::new(WorkspacePaneNode::leaf(primary_session_id.clone())),
             second: Box::new(WorkspacePaneNode::leaf(secondary_session_id.clone())),
         };
-        self.session_pane_roots.insert(tab_root, root);
+        self.shell.workspace.pane_roots.insert(tab_root, root);
         self.rebuild_session_tab_owners();
         self.activate_session_id(&secondary_session_id);
         self.sync_workspace_split_from_active_tab();
-        self.selected_nav = NavItem::Workspace;
-        self.main_mode = MainMode::Workspace;
+        self.shell.navigation.selected_nav = NavItem::Workspace;
+        self.shell.navigation.main_mode = MainMode::Workspace;
         self.persist_workspace_pane_layout();
         if self.startup_restore_complete {
             self.persist_open_tabs();
@@ -188,8 +180,8 @@ impl NyaTermApp {
         }
         self.activate_session_id_with_surface_sync(&session_id, cx);
         self.sync_workspace_split_from_active_tab();
-        self.selected_nav = NavItem::Workspace;
-        self.main_mode = MainMode::Workspace;
+        self.shell.navigation.selected_nav = NavItem::Workspace;
+        self.shell.navigation.main_mode = MainMode::Workspace;
         self.terminal.view.status = format!("focused pane {}", short_id(&session_id));
         cx.notify();
     }
@@ -241,18 +233,18 @@ impl NyaTermApp {
             return;
         };
         let tab_root = self.tab_root_for_session(&active_id);
-        let Some(root) = self.session_pane_roots.remove(&tab_root) else {
-            self.workspace_split = None;
+        let Some(root) = self.shell.workspace.pane_roots.remove(&tab_root) else {
+            self.shell.workspace.split = None;
             self.terminal.view.status = "workspace is not split".to_string();
             cx.notify();
             return;
         };
-        self.workspace_split_resize = None;
+        self.shell.workspace.split_resize = None;
 
         if let Some(collapsed) = collapse_around_session(root.clone(), &active_id) {
             match collapsed {
                 WorkspacePaneNode::Split { .. } => {
-                    self.session_pane_roots.insert(tab_root, collapsed);
+                    self.shell.workspace.pane_roots.insert(tab_root, collapsed);
                     self.terminal.view.status = "collapsed focused split".to_string();
                 }
                 WorkspacePaneNode::Leaf { session_id } => {
@@ -295,7 +287,7 @@ impl NyaTermApp {
             ) {
                 (Some(direction), Some(start_ratio)) => (direction, start_ratio),
                 _ => {
-                    let Some(root) = self.workspace_split.as_ref() else {
+                    let Some(root) = self.shell.workspace.split.as_ref() else {
                         return;
                     };
                     let Some(direction) = root.direction_for_split(&split_id) else {
@@ -308,7 +300,7 @@ impl NyaTermApp {
                 }
             }
         } else {
-            let Some(root) = self.workspace_split.as_ref() else {
+            let Some(root) = self.shell.workspace.split.as_ref() else {
                 return;
             };
             let Some(direction) = root.direction_for_split(&split_id) else {
@@ -323,7 +315,7 @@ impl NyaTermApp {
             WorkspaceSplitDirection::Horizontal => event.position.y,
             WorkspaceSplitDirection::Vertical => event.position.x,
         };
-        self.workspace_split_resize = Some(WorkspaceSplitResizeState {
+        self.shell.workspace.split_resize = Some(WorkspaceSplitResizeState {
             split_id,
             direction,
             start_pos,
@@ -339,7 +331,7 @@ impl NyaTermApp {
         event: &MouseMoveEvent,
         cx: &mut Context<Self>,
     ) {
-        let Some(state) = self.workspace_split_resize.clone() else {
+        let Some(state) = self.shell.workspace.split_resize.clone() else {
             return;
         };
         let current = match state.direction {
@@ -365,7 +357,7 @@ impl NyaTermApp {
             }
         }
         if !applied {
-            if let Some(root) = self.workspace_split.as_mut() {
+            if let Some(root) = self.shell.workspace.split.as_mut() {
                 if root.set_ratio_for_split(&state.split_id, next) {
                     applied = true;
                     self.write_back_active_tab_pane_root();
@@ -383,7 +375,7 @@ impl NyaTermApp {
         _event: &MouseUpEvent,
         cx: &mut Context<Self>,
     ) {
-        if let Some(state) = self.workspace_split_resize.take() {
+        if let Some(state) = self.shell.workspace.split_resize.take() {
             let ratio = self
                 .terminal
                 .windows
@@ -391,7 +383,9 @@ impl NyaTermApp {
                 .as_ref()
                 .and_then(|root| root.ratio_for_split(&state.split_id))
                 .or_else(|| {
-                    self.workspace_split
+                    self.shell
+                        .workspace
+                        .split
                         .as_ref()
                         .and_then(|root| root.ratio_for_split(&state.split_id))
                 });
@@ -401,7 +395,9 @@ impl NyaTermApp {
             if self.terminal_windows_is_multi_leaf() {
                 self.persist_terminal_window_layout();
             } else if self
-                .workspace_split
+                .shell
+                .workspace
+                .split
                 .as_ref()
                 .is_some_and(|root| root.is_split())
             {
@@ -472,12 +468,16 @@ impl NyaTermApp {
             .map(|session| session.id)
             .collect::<Vec<_>>();
         let layout = self
-            .workspace_split
+            .shell
+            .workspace
+            .split
             .as_ref()
             .filter(|root| root.is_split())
             .and_then(|root| root.serialize_layout(&ordered))
             .or_else(|| {
-                self.session_pane_roots
+                self.shell
+                    .workspace
+                    .pane_roots
                     .values()
                     .find(|root| root.is_split())
                     .and_then(|root| root.serialize_layout(&ordered))
@@ -496,16 +496,16 @@ impl NyaTermApp {
     }
 
     pub(in crate::features) fn try_restore_workspace_pane_layout(&mut self) {
-        if self.workspace_pane_layout_restored {
+        if self.shell.workspace.pane_layout_restored {
             return;
         }
         if !self.settings.startup_restore || !self.settings.startup_restore_window_layout {
-            self.workspace_pane_layout_restored = true;
+            self.shell.workspace.pane_layout_restored = true;
             return;
         }
         // Multi-leaf tab windows take visual precedence; skip pane restore when active.
         if self.terminal_windows_is_multi_leaf() {
-            self.workspace_pane_layout_restored = true;
+            self.shell.workspace.pane_layout_restored = true;
             return;
         }
         let ordered = self
@@ -516,11 +516,11 @@ impl NyaTermApp {
         if ordered.len() < 2 {
             // After startup finishes, don't keep waiting forever for a second tab.
             if self.startup_restore_complete {
-                self.workspace_pane_layout_restored = true;
+                self.shell.workspace.pane_layout_restored = true;
             }
             return;
         }
-        self.workspace_pane_layout_restored = true;
+        self.shell.workspace.pane_layout_restored = true;
         let Ok(store) = ConnectionStore::open_with_portable_key_path(
             self.runtime.config_dir(),
             self.runtime.portable_key_path().map(ToOwned::to_owned),
@@ -548,12 +548,12 @@ impl NyaTermApp {
         }
         // Install as a per-tab root under the first leaf (legacy global layout path).
         if let Some(first) = restored.session_ids().into_iter().next() {
-            self.session_pane_roots.insert(first, restored);
+            self.shell.workspace.pane_roots.insert(first, restored);
             self.rebuild_session_tab_owners();
             self.sync_workspace_split_from_active_tab();
         }
-        self.selected_nav = NavItem::Workspace;
-        self.main_mode = MainMode::Workspace;
+        self.shell.navigation.selected_nav = NavItem::Workspace;
+        self.shell.navigation.main_mode = MainMode::Workspace;
         self.terminal.view.status = "restored workspace pane layout".to_string();
     }
 }

crates/nyaterm-desktop/src/features/sync/cloud_sync_runtime/settings.rs

@@ -27,7 +27,7 @@ impl NyaTermApp {
                 || (!self.settings.has_master_password
                     && self.settings_master_password_draft.is_empty()))
         {
-            self.settings_active_tab = SettingsTab::Security;
+            self.shell.navigation.settings.active_tab = SettingsTab::Security;
             self.cloud_sync.status =
                 "configure a master password before enabling cloud sync".to_string();
             self.terminal.view.status = self.cloud_sync.status.clone();

crates/nyaterm-desktop/src/features/terminal/terminal_context_menu_runtime/action_links.rs

@@ -14,7 +14,7 @@ impl NyaTermApp {
         let Some(menu) = self.terminal.menus.action_link_menu.clone() else {
             return div().into_any_element();
         };
-        let (viewport_w, viewport_h) = self.last_viewport_size;
+        let (viewport_w, viewport_h) = self.shell.viewport.size;
         let (menu_x, menu_y) = clamp_menu_position(
             f32::from(menu.x),
             f32::from(menu.y),

crates/nyaterm-desktop/src/features/terminal/terminal_context_menu_runtime/menu.rs

@@ -143,7 +143,7 @@ impl NyaTermApp {
             };
         let _ = selection_link_kind;
 
-        let (viewport_w, viewport_h) = self.last_viewport_size;
+        let (viewport_w, viewport_h) = self.shell.viewport.size;
         // Approximate height from max-h for clamp (scrollable menus can be shorter).
         let (menu_x, menu_y) = clamp_menu_position(
             f32::from(menu.x),

crates/nyaterm-desktop/src/features/terminal/terminal_runtime/buffer.rs

@@ -890,7 +890,7 @@ impl NyaTermApp {
     }
 
     fn terminal_session_has_visible_surface(&self, session_id: &str) -> bool {
-        if session_id.is_empty() || self.main_mode != MainMode::Workspace {
+        if session_id.is_empty() || self.shell.navigation.main_mode != MainMode::Workspace {
             return false;
         }
         self.visible_terminal_session_ids()
@@ -899,7 +899,7 @@ impl NyaTermApp {
     }
 
     pub(in crate::features) fn visible_terminal_session_ids(&self) -> Vec<&str> {
-        if self.main_mode != MainMode::Workspace {
+        if self.shell.navigation.main_mode != MainMode::Workspace {
             return Vec::new();
         }
         if let Some(root) = self.terminal.windows.tree.as_ref()
@@ -907,7 +907,7 @@ impl NyaTermApp {
         {
             return terminal_window_node_visible_tab_ids(root);
         }
-        if let Some(root) = self.workspace_split.as_ref() {
+        if let Some(root) = self.shell.workspace.split.as_ref() {
             return workspace_pane_node_visible_session_ids(root);
         }
         self.session.active_id.iter().map(String::as_str).collect()

crates/nyaterm-desktop/src/features/terminal/terminal_runtime/sessions.rs

@@ -55,7 +55,7 @@ impl NyaTermApp {
         // Tauri: closing a strip tab closes the whole tab tree; closing a secondary leaf
         // only removes that pane. Strip close uses the tab-root id.
         let close_ids = if !self.is_secondary_pane_session(&session_id) {
-            if let Some(root) = self.session_pane_roots.get(&session_id) {
+            if let Some(root) = self.shell.workspace.pane_roots.get(&session_id) {
                 root.session_ids()
             } else {
                 vec![session_id.clone()]

crates/nyaterm-desktop/src/features/terminal/terminal_selection_runtime/action_links.rs

@@ -277,7 +277,9 @@ impl NyaTermApp {
         {
             return window_root.active_tabs();
         }
-        self.workspace_split
+        self.shell
+            .workspace
+            .split
             .as_ref()
             .map(|root| root.session_ids())
             .or_else(|| self.session.active_id.clone().map(|id| vec![id]))

crates/nyaterm-desktop/src/features/transfers/transfer_paths.rs

@@ -189,7 +189,7 @@ impl NyaTermApp {
         }
         let Some(config) = self.session.active_ssh_config.clone() else {
             self.terminal.view.status = "start an SSH session first".to_string();
-            self.selected_nav = NavItem::Transfers;
+            self.shell.navigation.selected_nav = NavItem::Transfers;
             cx.notify();
             return;
         };

docs/architecture/gpui-migration-status.md

@@ -9,7 +9,7 @@ Last updated from the working tree on 2026-07-28.
 
 | Metric | Current value | Notes |
 | --- | ---: | --- |
-| `NyaTermApp` fields | 102 | Counted from `features/app_state/mod.rs`; down from 585, still transitional. |
+| `NyaTermApp` fields | 55 | Counted from `features/app_state/mod.rs`; down from 585, still transitional. |
 | `impl NyaTermApp` blocks | 238 | Spread across 233 files under `crates/nyaterm-desktop/src`. |
 | `#[path = "..."]` declarations in desktop | 0 | Cleared. Every directory is a real module; the boundary script fails on any new occurrence. |
 | `use super::*` imports in desktop | 0 | Cleared in production and test modules; guarded crate-wide. |
@@ -331,11 +331,17 @@ these as staged extraction candidates, not as formatting-only refactor targets.
   retains session metadata/host queries, status messages, focus and redraw
   coordination. This state remains transient and changes no session or settings
   persistence format.
-- `ShellFeatureState` is the new owner for cross-view shell interaction state,
-  starting with the bottom-panel mode, quick-command/send-command heights and
-  resize lifecycle. Render helpers stay on views, and `NyaTermApp` still owns
-  settings persistence after a drag completes. This creates the boundary for a
-  later cohesive shell-chrome cut without introducing a mirror.
+- `ShellFeatureState` now owns the complete cross-view window interaction
+  cluster. Its `viewport`, `navigation`, `panels`, `chrome` and `workspace`
+  children contain geometry bookkeeping, settings navigation/window state,
+  side-panel stacks and resize lifecycles, title/tab menus and per-tab pane
+  ownership respectively; the existing `bottom_panel` child still owns its
+  mode, heights and drag state. Forty-seven top-level app fields became these
+  five focused children, so `NyaTermApp` dropped from 102 fields to 55 without
+  creating a writable mirror. Pure viewport, panel resize/stack resize, chrome
+  menu and workspace ownership transitions execute on the child states.
+  Render helpers remain on views, while `NyaTermApp` retains settings
+  persistence, GPUI notification, terminal coordination and event routing.
 - The Entity Store projection layer is gone entirely, in two steps.
 
   First, the six domain stores (`Ai`, `CloudSync`, `Connections`, `RemoteOps`,
@@ -1414,7 +1420,7 @@ honest remaining list.
    compiler-confirmed final pass also removed `features/prelude.rs`, so modules
    cannot regain the same implicit dependency surface through a shared import
    bucket.
-3. Largely done. `NyaTermApp` is down from 585 fields to 102, across seventeen
+3. Largely done. `NyaTermApp` is down from 585 fields to 55, across seventeen
    feature-state structs. The latest cohesive cuts moved sixteen terminal
    command-assistance and credential-prompt fields into
    `TerminalFeatureState::assist`, then seventeen transient settings fields
@@ -1424,9 +1430,11 @@ honest remaining list.
    conflict and GitHub device-flow state, recording and SSH-tunnel runtime
    resources with their job/UI lifecycle state, then the complete live session
    runtime with nested session-start, prompt and dialog ownership, then terminal
-   presentation runtime followed by sync-input, screen-lock and bottom-panel
-   interaction lifecycles. What is left is a long tail, and much of it is
-   genuinely app-level (stores, runtime, services, persisted collections).
+   presentation runtime followed by sync-input and screen-lock interaction
+   lifecycles, and finally forty-seven window interaction fields under the
+   shell's viewport, navigation, panel, chrome and workspace children. What is
+   left is a long tail, and much of it is genuinely app-level (stores, runtime,
+   services, persisted collections).
    Group by cohesion where a cluster exists; do not force the count down for
    its own sake.
    Method ownership is now moving too, which is what grouping the fields alone
@@ -1434,7 +1442,7 @@ honest remaining list.
    it belongs on that state, and the `NyaTermApp` method becomes a forwarder
    that owns `cx.notify()`. That is enforced by the type system rather than by
    convention — a handler taking `&mut TransferBrowserState` cannot reach the
-   session list no matter what a later edit tries. Eighty-four methods or
+   session list no matter what a later edit tries. More than one hundred methods or
    self-contained transitions have moved this way across transfers, security,
    the shell, sync input, the send command bar, AI, quick commands, cloud sync,
    recording, session starts and terminal paste review;
@@ -1445,7 +1453,9 @@ honest remaining list.
    of sync, closing a pending session start cannot update its maps without also
    applying the active pending/failed fallback rules, and paste editing cannot
    mutate its UTF-8 cursor without also clearing stale selection/IME state.
-   Those are the kinds of signals to look for.
+   Shell viewport timing, panel drags, mutually-exclusive tab menus and pane
+   ownership rebuilding now have the same property. Those are the kinds of
+   signals to look for.
    Two caveats worth keeping. Render helpers stay on the view even when they
    read one state — moving element construction onto a data struct trades one
    coupling for a worse one. And a method that reads a state plus `self.tr(...)`

scripts/check-architecture-boundaries.sh

@@ -128,6 +128,20 @@ check_no_matches \
   '^[[:space:]]*pub\(in crate::features\)[[:space:]]+(bottom_panel|quick_cmd_height|serial_send_height|bottom_panel_resize)[[:space:]]*:' \
   crates/nyaterm-desktop/src/features/app_state/mod.rs
 
+check_no_matches \
+  "window shell state must stay grouped under ShellFeatureState" \
+  '^[[:space:]]*pub\(in crate::features\)[[:space:]]+(last_viewport_size|wallpaper_tile_dimensions|last_viewport_change_at|title_drag_active_until|selected_nav|main_mode|settings_active_tab|settings_expanded_groups|settings_draft_snapshot|settings_window|settings_window_open_pending|settings_previous_left_collapsed|settings_previous_right_collapsed|active_left_panel|active_right_panel|left_open_panels|right_open_panels|panel_stack_sizes|panel_multi_open|right_focus|left_sidebar_collapsed|right_inspector_collapsed|mobile_left_open|mobile_right_open|left_panel_width|right_panel_width|panel_resize|panel_stack_resize|activity_bar_layout|activity_bar_context_menu|title_menu_open|title_menu_submenu|header_status|open_tabs_menu_open|new_session_menu_open|new_session_all_sessions_open|new_session_group_menu_path|session_tab_strip_scroll|session_tab_scroll_into_view_pending|last_connect_failure_name|last_connect_failure_error|workspace_split|workspace_split_resize|session_pane_roots|session_tab_owner|focused_terminal_window_leaf_id|workspace_pane_layout_restored)[[:space:]]*:' \
+  crates/nyaterm-desktop/src/features/app_state/mod.rs
+
+check_no_matches \
+  "panel resize transitions must stay on ShellPanelState" \
+  'PanelResizeState' \
+  crates/nyaterm-desktop/src/features/shell/panel_resize_runtime.rs
+check_no_matches \
+  "panel stack resize transitions must stay on ShellPanelState" \
+  'PanelStackResizeState' \
+  crates/nyaterm-desktop/src/features/shell/panel_stack_runtime.rs
+
 check_no_matches \
   "screen lock fields must stay grouped under SecurityFeatureState" \
   '^[[:space:]]*pub\(in crate::features\)[[:space:]]+(lock_focus|lock_password_draft|lock_status|is_locked|last_user_activity_at)[[:space:]]*:' \