refactor(tui): remove SidebarFocus and the classic sidebar's last state

Spec step 4 (part 2) of rail-unification-task-20260802 (checklist
section 2A). The type and every field it hung off of are gone; nothing
in the tree can mutate or gate on a panel system that no longer exists.

- app.rs: SidebarFocus the enum, its from_setting/as_setting impls,
  App.sidebar_focus, App.sidebar_width_percent, set_sidebar_focus, and
  the whole classic interaction block (sidebar_resizing/_hovered,
  resize anchors, last_sidebar_area/_host_width/_handle_area,
  sidebar_resize_total_width), plus ViewportState.last_sidebar_area.
- app/init.rs: the settings reads and field initializers for all of the
  above.
- subagent_routing: agents_sidebar_surface_visible now means what it
  says in the rail world (panel == Agents && last_area);
  agents_panel_has_content (auto-mode remnant) deleted.
- sidebar.rs: the five explicit_tasks_focus gates re-point at
  work_surface.panel == RailPanel::Tasks; orphaned ratatui/theme imports
  dropped.
- mouse_ui.rs: approval wheel ownership and the context-menu on_sidebar
  gate re-point at work_surface.last_area (rail rows keep their
  right-click Run/Copy menu via the shared hover sections);
  sidebar_click_action was already section-driven and is untouched; the
  scroll-leak consume block for the never-Some legacy rect is deleted.
- settings.rs: sidebar_width_percent and sidebar_focus become load-only
  migration shims (#[serde(skip_serializing)] — read by
  migrate_sidebar_settings_to_rail, never written back);
  update_sidebar_width deleted.
- ui.rs: the per-frame reset of the deleted fields is gone (the live
  sidebar_hover_tooltip clear stays).

Tests: sidebar.rs setups (~30) and ui/app tests re-point at
work_surface.panel/placement/last_area; entering_operate_preserves_
user_rail_panel replaces the sidebar_focus variant; the approval-wheel
test drops the legacy rect (rail ownership covered by the work_surface
arm); the two loading-hover tests keep their assertions against the
generic tooltip-clear path; context-menu tests drive the rail's
work_surface.last_area; sidebar_focus from_setting coverage lives on in
the settings migration tests.

Gates: cargo fmt --check -p codewhale-tui clean;
sidebar: 129 passed; mouse: 70; hotbar: 92; footer: 104; settings: 121;
commands: 760; work_surface: 64 — all 0 failed.

crates/tui/src/settings.rs

@@ -387,9 +387,14 @@ pub struct Settings {
     /// Default mode: "agent" (Act), "plan", or "operate". Legacy permission
     /// shorthands are accepted for migration but never advertised as modes.
     pub default_mode: String,
-    /// Sidebar width as percentage of terminal width
+    /// Legacy sidebar width as percentage of terminal width. Load-only
+    /// migration shim (0.9.4 rail unification): read by
+    /// `migrate_sidebar_settings_to_rail`, never written back.
+    #[serde(skip_serializing)]
     pub sidebar_width_percent: u16,
-    /// Sidebar focus mode: pinned, auto, tasks, agents, context, hidden
+    /// Legacy sidebar focus mode: pinned, auto, tasks, agents, context,
+    /// hidden. Load-only migration shim, never written back.
+    #[serde(skip_serializing)]
     pub sidebar_focus: String,
     /// Enable the session-context panel (#504). Shows working set, tokens,
     /// cost, MCP/LSP status, cycle count, and memory info.
@@ -1128,12 +1133,6 @@ impl Settings {
         atomically_replace_settings_file(path, body.as_bytes())
     }
 
-    /// Update and persist sidebar width percentage (10-50) — used by the
-    /// drag-to-resize handle in the TUI.
-    pub fn update_sidebar_width(&mut self, percent: u16) {
-        self.sidebar_width_percent = percent.clamp(10, 50);
-    }
-
     /// Set a single setting by key
     pub fn set(&mut self, key: &str, value: &str) -> Result<()> {
         match key {

crates/tui/src/tui/app.rs

@@ -292,21 +292,6 @@ pub struct TurnCacheRecord {
     pub recorded_at: Instant,
 }
 
-/// Sidebar content focus mode.
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub enum SidebarFocus {
-    Auto,
-    Pinned,
-    Tasks,
-    Agents,
-    Context,
-    /// Dedicated Sessions browser panel (#2934). Renders the persistent
-    /// sessions rail as the sole sidebar content, regardless of whether the
-    /// `sessions_rail` setting is enabled. Focuses session navigation.
-    Sessions,
-    Hidden,
-}
-
 /// Browsing context captured when the `/model` picker is dismissed (#4109).
 /// Plain data so `App` does not depend on the picker's internal view enum.
 #[derive(Debug, Clone, PartialEq, Eq)]
@@ -482,36 +467,6 @@ impl Default for LspRepairState {
     }
 }
 
-impl SidebarFocus {
-    #[must_use]
-    pub fn from_setting(value: &str) -> Self {
-        match value.trim().to_ascii_lowercase().as_str() {
-            "pinned" | "visible" | "show" | "on" | "work" | "plan" | "todos" => Self::Pinned,
-            // Persist/compat key remains "tasks"; user-facing panel is Activity (#4147/#4135).
-            "tasks" | "activity" | "live" | "running" => Self::Tasks,
-            "agents" | "subagents" | "sub-agents" => Self::Agents,
-            "context" => Self::Context,
-            "sessions" | "sessions_rail" | "session_history" => Self::Sessions,
-            "hidden" | "hide" | "closed" | "off" | "none" => Self::Hidden,
-            _ => Self::Auto,
-        }
-    }
-
-    #[must_use]
-    #[allow(dead_code)]
-    pub fn as_setting(self) -> &'static str {
-        match self {
-            Self::Auto => "auto",
-            Self::Pinned => "pinned",
-            Self::Tasks => "tasks",
-            Self::Agents => "agents",
-            Self::Context => "context",
-            Self::Sessions => "sessions",
-            Self::Hidden => "hidden",
-        }
-    }
-}
-
 /// Pre-session launch menu state for the underwater shell.
 ///
 /// This is deliberately separate from onboarding and from the post-launch
@@ -685,10 +640,6 @@ pub struct ViewportState {
     /// Painted band occupied by the active inline approval. Stored so wheel
     /// routing can prefer the visible card over side surfaces underneath it.
     pub last_approval_area: Option<Rect>,
-    /// Outer rect of the right-hand sidebar (when visible), stored at render
-    /// time so mouse hit-testing can keep scroll events over the sidebar from
-    /// leaking into the transcript viewport.
-    pub last_sidebar_area: Option<Rect>,
     /// WorkflowPanel rect above the composer (#4121), for mouse toggle/cancel.
     pub last_workflow_panel_area: Option<Rect>,
     pub last_workflow_cancel_area: Option<Rect>,
@@ -721,7 +672,6 @@ impl Default for ViewportState {
             last_transcript_area: None,
             last_composer_area: None,
             last_approval_area: None,
-            last_sidebar_area: None,
             last_workflow_panel_area: None,
             last_workflow_cancel_area: None,
             last_transcript_top: 0,
@@ -1391,8 +1341,6 @@ pub struct App {
     /// Toggled by `/voice-control`.
     pub voice_control_enabled: bool,
     pub transcript_spacing: TranscriptSpacing,
-    pub sidebar_width_percent: u16,
-    pub sidebar_focus: SidebarFocus,
     /// Sidebar hover state for mouse tooltip support.
     pub sidebar_hover: SidebarHoverState,
     /// Current hover tooltip text, if any.
@@ -1408,23 +1356,6 @@ pub struct App {
     pub provider_picker_memory: Option<ProviderPickerMemory>,
     /// Last known mouse position for tooltip placement.
     pub last_mouse_pos: Option<(u16, u16)>,
-    /// Whether the user is currently dragging the sidebar resize handle.
-    pub sidebar_resizing: bool,
-    /// Whether the pointer is over the classic sidebar resize handle.
-    pub sidebar_resize_hovered: bool,
-    /// Mouse column at the start of a sidebar-resize drag.
-    pub sidebar_resize_anchor_x: u16,
-    /// Sidebar width in columns at the start of a sidebar-resize drag.
-    pub sidebar_resize_anchor_width: u16,
-    /// Last sidebar area rendered (for mouse hit-testing the resize handle).
-    pub last_sidebar_area: Option<Rect>,
-    /// Last total chat/sidebar width considered for sidebar rendering.
-    pub last_sidebar_host_width: Option<u16>,
-    /// Handle rect painted on the left edge of the sidebar (1 col).
-    pub last_sidebar_handle_area: Option<Rect>,
-    /// Total horizontal space (chat + sidebar) used to compute the percentage
-    /// during sidebar resize drag.
-    pub sidebar_resize_total_width: u16,
     /// Whether the session-context panel is enabled (#504).
     pub context_panel: bool,
     /// Whether the persistent Sessions rail is enabled (#2934). Opt-in.
@@ -4097,13 +4028,6 @@ impl App {
         }
     }
 
-    pub fn set_sidebar_focus(&mut self, focus: SidebarFocus) {
-        if self.sidebar_focus != focus {
-            self.sidebar_focus = focus;
-        }
-        self.needs_redraw = true;
-    }
-
     pub fn close_slash_menu(&mut self) {
         self.slash_menu_hidden = true;
         self.needs_redraw = true;

crates/tui/src/tui/app/init.rs

@@ -241,8 +241,6 @@ impl App {
             .trim()
             .eq_ignore_ascii_case("vim");
         let transcript_spacing = TranscriptSpacing::from_setting(&settings.transcript_spacing);
-        let sidebar_width_percent = settings.sidebar_width_percent;
-        let sidebar_focus = SidebarFocus::from_setting(&settings.sidebar_focus);
         let max_input_history = settings.max_input_history;
         let use_paste_burst_detection = settings.paste_burst_detection;
         // Resolve the named theme from settings; unknown values were already
@@ -714,22 +712,12 @@ impl App {
             voice_send_enabled: false,
             voice_control_enabled: false,
             transcript_spacing,
-            sidebar_width_percent,
-            sidebar_focus,
             sidebar_hover: SidebarHoverState::default(),
             sidebar_hover_tooltip: None,
             cached_work_summary: None,
             model_picker_memory: None,
             provider_picker_memory: None,
             last_mouse_pos: None,
-            sidebar_resizing: false,
-            sidebar_resize_hovered: false,
-            sidebar_resize_anchor_x: 0,
-            sidebar_resize_anchor_width: 0,
-            last_sidebar_area: None,
-            last_sidebar_host_width: None,
-            last_sidebar_handle_area: None,
-            sidebar_resize_total_width: 0,
             context_panel: settings.context_panel,
             sessions_rail: settings.sessions_rail,
             sessions_rail_cache: None,

crates/tui/src/tui/app/tests.rs

@@ -1682,35 +1682,6 @@ fn cny_cache_savings_falls_back_to_usd_for_usd_only_models() {
     assert!((savings - 0.79).abs() < 1e-9, "got {savings}");
 }
 
-#[test]
-fn sidebar_focus_accepts_pinned_and_maps_legacy_trackers_to_pinned() {
-    assert_eq!(SidebarFocus::from_setting("auto"), SidebarFocus::Auto);
-    assert_eq!(SidebarFocus::from_setting("pinned"), SidebarFocus::Pinned);
-    assert_eq!(SidebarFocus::from_setting("work"), SidebarFocus::Pinned);
-    assert_eq!(SidebarFocus::from_setting("plan"), SidebarFocus::Pinned);
-    assert_eq!(SidebarFocus::from_setting("todos"), SidebarFocus::Pinned);
-    assert_eq!(SidebarFocus::from_setting("tasks"), SidebarFocus::Tasks);
-    assert_eq!(SidebarFocus::from_setting("activity"), SidebarFocus::Tasks);
-    assert_eq!(SidebarFocus::from_setting("live"), SidebarFocus::Tasks);
-    assert_eq!(SidebarFocus::from_setting("running"), SidebarFocus::Tasks);
-    assert_eq!(SidebarFocus::from_setting("agents"), SidebarFocus::Agents);
-    assert_eq!(SidebarFocus::from_setting("context"), SidebarFocus::Context);
-    assert_eq!(SidebarFocus::from_setting("sessions"), SidebarFocus::Sessions);
-    assert_eq!(
-        SidebarFocus::from_setting("sessions_rail"),
-        SidebarFocus::Sessions
-    );
-    assert_eq!(
-        SidebarFocus::from_setting("session_history"),
-        SidebarFocus::Sessions
-    );
-    assert_eq!(SidebarFocus::from_setting("hidden"), SidebarFocus::Hidden);
-    assert_eq!(SidebarFocus::from_setting("off"), SidebarFocus::Hidden);
-    assert_eq!(SidebarFocus::Pinned.as_setting(), "pinned");
-    assert_eq!(SidebarFocus::Hidden.as_setting(), "hidden");
-    assert_eq!(SidebarFocus::Sessions.as_setting(), "sessions");
-}
-
 #[test]
 fn slash_command_classifier_treats_absolute_path_as_message() {
     assert!(looks_like_slash_command_input("/"));
@@ -2873,12 +2844,15 @@ fn clear_todos_is_atomic_and_invalidates_cached_work_summary() {
 }
 
 #[test]
-fn entering_operate_preserves_user_sidebar_focus() {
+fn entering_operate_preserves_user_rail_panel() {
     let mut app = App::new(test_options(false), &Config::default());
-    app.sidebar_focus = SidebarFocus::Tasks;
+    app.work_surface.panel = crate::tui::work_surface::RailPanel::Agents;
 
     assert!(app.set_mode(AppMode::Operate));
-    assert_eq!(app.sidebar_focus, SidebarFocus::Tasks);
+    assert_eq!(
+        app.work_surface.panel,
+        crate::tui::work_surface::RailPanel::Agents
+    );
 }
 
 #[test]

crates/tui/src/tui/footer_ui.rs

@@ -383,10 +383,11 @@ mod tests {
         let options = TuiOptions {
             ..crate::test_support::test_tui_options(PathBuf::from("."))
         };
-        // Pin sidebar so dogfood machines with Agents-visible settings.toml
-        // do not hide the footer agents chip this test asserts.
+        // Pin the rail panel so dogfood machines whose settings.toml migrates
+        // a legacy Agents sidebar focus do not hide the footer agents chip
+        // this test asserts.
         let mut app = App::new(options, &Config::default());
-        app.sidebar_focus = crate::tui::app::SidebarFocus::Hidden;
+        app.work_surface.panel = crate::tui::work_surface::RailPanel::Tasks;
         app
     }
 

crates/tui/src/tui/hotbar/actions.rs

@@ -8,7 +8,7 @@ use crate::commands::{self, CommandInfo, CommandResult};
 use crate::config::{ApiProvider, Config};
 use crate::localization::{Locale, MessageId, tr};
 use crate::provider_lake::all_catalog_models_for_provider;
-use crate::tui::app::{App, AppAction, AppMode, SidebarFocus};
+use crate::tui::app::{App, AppAction, AppMode};
 use crate::tui::command_palette::{
     CommandPaletteView, build_entries as build_command_palette_entries,
 };

crates/tui/src/tui/mouse_ui.rs

@@ -44,7 +44,6 @@ pub(crate) fn should_drop_loading_mouse_motion(app: &App, mouse: MouseEvent) ->
             // these events wedges the resize state mid-drag (#3063).
             !app.viewport.transcript_selection.dragging
                 && !app.viewport.transcript_scrollbar_dragging
-                && !app.sidebar_resizing
                 && !app.work_surface.is_resizing()
         }
         _ => false,
@@ -298,8 +297,7 @@ pub(crate) fn handle_mouse_event(app: &mut App, mouse: MouseEvent) -> Vec<ViewEv
     // Other modals still own their wheel input exclusively (#4371).
     if app.view_stack.top_kind() == Some(ModalKind::Approval) {
         let over_approval = mouse_hits_rect(mouse, app.viewport.last_approval_area);
-        let over_side_surface = mouse_hits_rect(mouse, app.viewport.last_sidebar_area)
-            || mouse_hits_rect(mouse, app.work_surface.last_area);
+        let over_side_surface = mouse_hits_rect(mouse, app.work_surface.last_area);
         match mouse.kind {
             MouseEventKind::ScrollUp => {
                 if over_approval || !over_side_surface {
@@ -385,22 +383,6 @@ pub(crate) fn handle_mouse_event(app: &mut App, mouse: MouseEvent) -> Vec<ViewEv
         return Vec::new();
     }
 
-    // Scroll events while the cursor is over the right-hand sidebar must not
-    // drive the transcript scroll. The sidebar is a fixed dashboard with no
-    // scroll state of its own, so consume the wheel event instead of leaking
-    // it into the transcript viewport behind it.
-    if matches!(
-        mouse.kind,
-        MouseEventKind::ScrollUp | MouseEventKind::ScrollDown
-    ) && app.viewport.last_sidebar_area.is_some_and(|area| {
-        mouse.column >= area.x
-            && mouse.column < area.x.saturating_add(area.width)
-            && mouse.row >= area.y
-            && mouse.row < area.y.saturating_add(area.height)
-    }) {
-        return Vec::new();
-    }
-
     match mouse.kind {
         MouseEventKind::Moved => {
             // Update last mouse position for tooltip rendering + hover layer.
@@ -1107,7 +1089,7 @@ pub(crate) fn open_context_menu(app: &mut App, mouse: MouseEvent) {
 pub(crate) fn build_context_menu_entries(app: &App, mouse: MouseEvent) -> Vec<ContextMenuEntry> {
     let mut entries = Vec::new();
     let mut git_path = None;
-    let on_sidebar = mouse_hits_rect(mouse, app.viewport.last_sidebar_area);
+    let on_sidebar = mouse_hits_rect(mouse, app.work_surface.last_area);
 
     if on_sidebar {
         if let Some(command) = sidebar_click_action(app, mouse)
@@ -1680,7 +1662,7 @@ mod tests {
     #[test]
     fn context_menu_keeps_paste_first_outside_sidebar() {
         let mut app = create_test_app();
-        app.viewport.last_sidebar_area = Some(Rect::new(60, 4, 20, 6));
+        app.work_surface.last_area = Some(Rect::new(60, 4, 20, 6));
 
         let entries = build_context_menu_entries(&app, right_click(10, 4));
 
@@ -1693,7 +1675,7 @@ mod tests {
     #[test]
     fn sidebar_context_menu_omits_paste_without_row_action() {
         let mut app = create_test_app();
-        app.viewport.last_sidebar_area = Some(Rect::new(60, 4, 20, 6));
+        app.work_surface.last_area = Some(Rect::new(60, 4, 20, 6));
         app.sidebar_hover.sections.push(SidebarHoverSection {
             content_area: Rect::new(60, 4, 20, 6),
             lines: vec!["header".to_string()],
@@ -1713,7 +1695,7 @@ mod tests {
     #[test]
     fn sidebar_context_menu_runs_clickable_row_action() {
         let mut app = create_test_app();
-        app.viewport.last_sidebar_area = Some(Rect::new(60, 4, 20, 6));
+        app.work_surface.last_area = Some(Rect::new(60, 4, 20, 6));
         app.sidebar_hover.sections.push(SidebarHoverSection {
             content_area: Rect::new(60, 4, 20, 6),
             lines: vec!["job row".to_string()],
@@ -1793,7 +1775,7 @@ mod tests {
     #[test]
     fn sidebar_click_routes_inline_stop_zone_before_row_action() {
         let mut app = create_test_app();
-        app.viewport.last_sidebar_area = Some(Rect::new(60, 4, 20, 4));
+        app.work_surface.last_area = Some(Rect::new(60, 4, 20, 4));
         app.sidebar_hover.sections.push(SidebarHoverSection {
             content_area: Rect::new(60, 4, 20, 4),
             lines: vec!["job row [x]".to_string()],
@@ -1819,7 +1801,7 @@ mod tests {
     #[test]
     fn sidebar_click_routes_agent_inline_stop_zone_before_peek_action() {
         let mut app = create_test_app();
-        app.viewport.last_sidebar_area = Some(Rect::new(60, 4, 24, 4));
+        app.work_surface.last_area = Some(Rect::new(60, 4, 24, 4));
         app.sidebar_hover.sections.push(SidebarHoverSection {
             content_area: Rect::new(60, 4, 24, 4),
             lines: vec!["[~] worker Agent 1 [x]".to_string()],
@@ -1854,7 +1836,7 @@ mod tests {
     #[test]
     fn sidebar_context_menu_offers_copy_of_hovered_row() {
         let mut app = create_test_app();
-        app.viewport.last_sidebar_area = Some(Rect::new(60, 4, 20, 6));
+        app.work_surface.last_area = Some(Rect::new(60, 4, 20, 6));
         app.sidebar_hover.sections.push(SidebarHoverSection {
             content_area: Rect::new(60, 4, 20, 6),
             lines: vec!["agent row".to_string()],

crates/tui/src/tui/sidebar.rs

@@ -13,28 +13,22 @@ use crate::localization::Locale;
 use crate::tui::app::HuntVerdict;
 
 use ratatui::{
-    Frame,
     layout::Rect,
-    prelude::Widget,
     style::Style,
     text::{Line, Span},
-    widgets::{Block, Paragraph, Wrap},
 };
 
-use crate::deepseek_theme::Theme;
 use crate::palette;
 use crate::tools::subagent::{AgentWorkerStatus, SubAgentStatus, localized_whale_display_names};
 use crate::tools::todo::TodoStatus;
 
 use super::app::{
-    AgentCurrentActivity, AgentCurrentActivityStatus, App, SidebarFocus, SidebarHoverRow,
-    SidebarHoverSection, SidebarRowAction, TaskPanelEntry, TaskPanelEntryKind,
+    AgentCurrentActivity, AgentCurrentActivityStatus, App, SidebarHoverRow, SidebarRowAction,
+    TaskPanelEntry, TaskPanelEntryKind,
 };
 use super::history::{GenericToolCell, HistoryCell, ToolCell, ToolStatus, summarize_tool_output};
 use super::motion::MotionPolicy;
 use super::spinner::{LIVE_MARKER_DELAY_MS, braille_spinner_frame_for_elapsed_ms};
-use super::subagent_routing::active_fanout_counts;
-use super::ui::FILE_TREE_MIN_HOST_WIDTH;
 use super::ui_text::{concise_shell_command_label, truncate_line_to_width};
 
 /// Tolerance for floating-point cost comparison in the sidebar breakdown.
@@ -811,7 +805,7 @@ struct TaskPanelRowSets {
 }
 
 fn task_panel_row_sets(app: &App) -> TaskPanelRowSets {
-    let explicit_tasks_focus = app.sidebar_focus == SidebarFocus::Tasks;
+    let explicit_tasks_focus = app.work_surface.panel == crate::tui::work_surface::RailPanel::Tasks;
     let active = active_tool_rows(app);
     // Auto/Pinned mode deliberately skips live-tool dedup (passes an empty
     // slice), matching the previous per-consumer call sites.
@@ -845,7 +839,7 @@ fn task_panel_rows(
     let theme = &app.ui_theme;
     let mut lines: Vec<Line<'static>> = Vec::with_capacity(max_rows.max(4));
     let mut actions: Vec<Option<SidebarRowAction>> = Vec::with_capacity(max_rows.max(4));
-    let explicit_tasks_focus = app.sidebar_focus == SidebarFocus::Tasks;
+    let explicit_tasks_focus = app.work_surface.panel == crate::tui::work_surface::RailPanel::Tasks;
 
     if explicit_tasks_focus && app.runtime_turn_id.is_some() {
         let status = app
@@ -986,7 +980,7 @@ fn task_panel_rows(
     // Yank hint: surface the keyboard path for copying the focused task/turn ID.
     if lines.len() + 1 < max_rows
         && app.runtime_turn_id.is_some()
-        && app.sidebar_focus == SidebarFocus::Tasks
+        && app.work_surface.panel == crate::tui::work_surface::RailPanel::Tasks
     {
         lines.push(Line::from(Span::styled(
             "y → copy turn id  ·  Y → copy full status",
@@ -1016,7 +1010,7 @@ fn task_panel_rows(
 
 fn task_panel_hover_texts(app: &App, row_sets: &TaskPanelRowSets, max_rows: usize) -> Vec<String> {
     let mut texts = Vec::with_capacity(max_rows.max(4));
-    let explicit_tasks_focus = app.sidebar_focus == SidebarFocus::Tasks;
+    let explicit_tasks_focus = app.work_surface.panel == crate::tui::work_surface::RailPanel::Tasks;
 
     if explicit_tasks_focus && let Some(turn_id) = app.runtime_turn_id.as_ref() {
         let status = app.runtime_turn_status.as_deref().unwrap_or("unknown");
@@ -1094,7 +1088,7 @@ fn task_panel_hover_texts(app: &App, row_sets: &TaskPanelRowSets, max_rows: usiz
 
     if texts.len() + 1 < max_rows
         && app.runtime_turn_id.is_some()
-        && app.sidebar_focus == SidebarFocus::Tasks
+        && app.work_surface.panel == crate::tui::work_surface::RailPanel::Tasks
     {
         texts.push("y -> copy turn id  ·  Y -> copy full status".to_string());
     }
@@ -2854,16 +2848,15 @@ fn agent_stop_action_for_click(action: &SidebarRowAction) -> Option<SidebarRowAc
 mod tests {
     use super::{
         ACTIVE_TOOL_COMPLETED_ROW_TTL, ACTIVE_TOOL_STALE_RUNNING_ROW_TTL, HotbarSlotState,
-        SidebarAgentRow, SidebarFocus, SidebarHoverRow, SidebarHoverSection,
-        SidebarSubagentSummary, SidebarToolRow, SidebarWorkChecklistItem, SidebarWorkSummary,
-        ToolRowOrder, agent_row_hover_text, background_task_spinner_prefix,
-        cached_agent_activity_is_live, context_panel_cost_line, editorial_tool_rows,
-        hotbar_panel_enabled, hotbar_panel_hover_texts, hotbar_panel_lines, hotbar_panel_slots,
-        normalize_activity_text, sidebar_agent_rows, sidebar_hover_rows, sidebar_work_summary,
-        sort_sidebar_agent_rows_as_tree, subagent_output_handle, subagent_panel_hover_texts,
-        subagent_panel_lines, subagent_panel_rows, task_panel_hover_texts, task_panel_lines,
-        task_panel_row_sets, task_panel_rows, work_panel_empty_hint, work_panel_hover_texts,
-        work_panel_lines,
+        SidebarAgentRow, SidebarHoverRow, SidebarSubagentSummary, SidebarToolRow,
+        SidebarWorkChecklistItem, SidebarWorkSummary, ToolRowOrder, agent_row_hover_text,
+        background_task_spinner_prefix, cached_agent_activity_is_live, context_panel_cost_line,
+        editorial_tool_rows, hotbar_panel_enabled, hotbar_panel_hover_texts, hotbar_panel_lines,
+        hotbar_panel_slots, normalize_activity_text, sidebar_agent_rows, sidebar_hover_rows,
+        sidebar_work_summary, sort_sidebar_agent_rows_as_tree, subagent_output_handle,
+        subagent_panel_hover_texts, subagent_panel_lines, subagent_panel_rows,
+        task_panel_hover_texts, task_panel_lines, task_panel_row_sets, task_panel_rows,
+        work_panel_empty_hint, work_panel_hover_texts, work_panel_lines,
     };
     use crate::config::Config;
     use crate::localization::Locale;
@@ -2873,8 +2866,8 @@ mod tests {
     use crate::tui::active_cell::ActiveCell;
     use crate::tui::app::{
         AgentCurrentActivity, AgentCurrentActivityStatus, AgentProgressMeta, App, AppMode,
-        HuntVerdict, SidebarHoverState, SidebarRowAction, TaskPanelEntry, TaskPanelEntryKind,
-        TuiOptions,
+        HuntVerdict, SidebarHoverSection, SidebarHoverState, SidebarRowAction, TaskPanelEntry,
+        TaskPanelEntryKind, TuiOptions,
     };
     use crate::tui::history::{
         ExecCell, ExecSource, GenericToolCell, HistoryCell, ToolCell, ToolStatus,
@@ -3161,7 +3154,7 @@ mod tests {
         // `hotbar_panel_slots_resolve_configured_bindings_and_active_state`.
         let mut app = create_test_app();
         app.mode = AppMode::Agent;
-        app.sidebar_focus = SidebarFocus::Pinned;
+        app.work_surface.panel = crate::tui::work_surface::RailPanel::Pinned;
 
         assert!(
             !hotbar_panel_enabled(&app, &Config::default()),
@@ -3190,7 +3183,7 @@ mod tests {
     fn hotbar_panel_slots_resolve_configured_bindings_and_active_state() {
         let mut app = create_test_app();
         app.mode = AppMode::Agent;
-        app.sidebar_focus = SidebarFocus::Pinned;
+        app.work_surface.panel = crate::tui::work_surface::RailPanel::Pinned;
         let config = Config {
             hotbar: Some(
                 codewhale_config::default_hotbar_bindings()
@@ -3285,7 +3278,7 @@ mod tests {
     fn hotbar_panel_lines_keep_two_fixed_rows_and_hover_status() {
         let mut app = create_test_app();
         app.mode = AppMode::Agent;
-        app.sidebar_focus = SidebarFocus::Pinned;
+        app.work_surface.panel = crate::tui::work_surface::RailPanel::Pinned;
         let config = Config {
             hotbar: Some(
                 codewhale_config::default_hotbar_bindings()
@@ -3799,7 +3792,7 @@ mod tests {
         assert!(!joined.contains("Strategy") && !joined.contains("route "));
 
         let mut app = create_test_app();
-        app.sidebar_focus = SidebarFocus::Tasks;
+        app.work_surface.panel = crate::tui::work_surface::RailPanel::Tasks;
         let activity = lines_to_text(&task_panel_lines(&app, 48, 4));
         assert!(
             activity
@@ -3816,7 +3809,7 @@ mod tests {
     #[test]
     fn tasks_panel_renders_active_tool_rows_before_background_empty_state() {
         let mut app = create_test_app();
-        app.sidebar_focus = SidebarFocus::Tasks;
+        app.work_surface.panel = crate::tui::work_surface::RailPanel::Tasks;
         let mut active = ActiveCell::new();
         active.push_tool(
             "tool-1",
@@ -3856,7 +3849,7 @@ mod tests {
     #[test]
     fn tasks_panel_renders_recent_completed_tool_rows() {
         let mut app = create_test_app();
-        app.sidebar_focus = SidebarFocus::Tasks;
+        app.work_surface.panel = crate::tui::work_surface::RailPanel::Tasks;
         app.history
             .push(HistoryCell::Tool(ToolCell::Generic(GenericToolCell {
                 name: "read_file".to_string(),
@@ -3884,7 +3877,7 @@ mod tests {
     #[test]
     fn tasks_panel_expires_completed_active_tool_rows() {
         let mut app = create_test_app();
-        app.sidebar_focus = SidebarFocus::Tasks;
+        app.work_surface.panel = crate::tui::work_surface::RailPanel::Tasks;
         let mut active = ActiveCell::new();
         active.push_tool(
             "tool-1",
@@ -3924,7 +3917,7 @@ mod tests {
     #[test]
     fn tasks_panel_lingers_fresh_completed_active_tool_rows() {
         let mut app = create_test_app();
-        app.sidebar_focus = SidebarFocus::Tasks;
+        app.work_surface.panel = crate::tui::work_surface::RailPanel::Tasks;
         let mut active = ActiveCell::new();
         active.push_tool(
             "tool-1",
@@ -3983,7 +3976,7 @@ mod tests {
             files_touched: 0,
         });
 
-        app.sidebar_focus = SidebarFocus::Tasks;
+        app.work_surface.panel = crate::tui::work_surface::RailPanel::Tasks;
         let focused = task_panel_row_sets(&app);
         assert!(
             focused.background.is_empty(),
@@ -3991,7 +3984,7 @@ mod tests {
             focused.background
         );
 
-        app.sidebar_focus = SidebarFocus::Auto;
+        app.work_surface.panel = crate::tui::work_surface::RailPanel::Pinned;
         let auto = task_panel_row_sets(&app);
         assert_eq!(
             auto.background.len(),
@@ -4003,7 +3996,7 @@ mod tests {
     #[test]
     fn task_panel_rows_and_hover_share_one_snapshot() {
         let mut app = create_test_app();
-        app.sidebar_focus = SidebarFocus::Tasks;
+        app.work_surface.panel = crate::tui::work_surface::RailPanel::Tasks;
         app.runtime_turn_id = Some("turn_abcdef123456".to_string());
         app.runtime_turn_status = Some("in_progress".to_string());
         app.turn_counter = 3;
@@ -4051,7 +4044,7 @@ mod tests {
     #[test]
     fn tasks_panel_collapses_stale_running_tool_rows() {
         let mut app = create_test_app();
-        app.sidebar_focus = SidebarFocus::Tasks;
+        app.work_surface.panel = crate::tui::work_surface::RailPanel::Tasks;
         let mut active = ActiveCell::new();
         for (idx, command) in ["long one", "long two"].into_iter().enumerate() {
             active.push_tool(
@@ -4090,7 +4083,7 @@ mod tests {
     #[test]
     fn tasks_panel_does_not_double_count_running_shell_job_as_live_and_background() {
         let mut app = create_test_app();
-        app.sidebar_focus = SidebarFocus::Tasks;
+        app.work_surface.panel = crate::tui::work_surface::RailPanel::Tasks;
         let mut active = ActiveCell::new();
         active.push_tool(
             "shell-1",
@@ -4358,10 +4351,10 @@ mod tests {
     }
 
     #[test]
-    fn tasks_panel_auto_mode_shows_only_live_background_jobs() {
+    fn tasks_panel_non_tasks_mode_shows_only_live_background_jobs() {
         let mut app = create_test_app();
         app.low_motion = false;
-        app.sidebar_focus = SidebarFocus::Auto;
+        app.work_surface.panel = crate::tui::work_surface::RailPanel::Pinned;
         app.runtime_turn_id = Some("turn_abcdef123456".to_string());
         app.runtime_turn_status = Some("in_progress".to_string());
         let mut active = ActiveCell::new();
@@ -4435,7 +4428,7 @@ mod tests {
     #[test]
     fn tasks_panel_keeps_model_reasoning_in_transcript_only() {
         let mut app = create_test_app();
-        app.sidebar_focus = SidebarFocus::Tasks;
+        app.work_surface.panel = crate::tui::work_surface::RailPanel::Tasks;
         app.runtime_turn_id = Some("turn_reasoning".to_string());
         app.runtime_turn_status = Some("in_progress".to_string());
         app.history.push(HistoryCell::Thinking {
@@ -4459,7 +4452,7 @@ mod tests {
     #[test]
     fn task_panel_actions_make_single_background_job_clickable() {
         let mut app = create_test_app();
-        app.sidebar_focus = SidebarFocus::Tasks;
+        app.work_surface.panel = crate::tui::work_surface::RailPanel::Tasks;
         app.task_panel.push(TaskPanelEntry {
             id: "shell_only".to_string(),
             status: "running".to_string(),
@@ -4502,7 +4495,7 @@ mod tests {
     #[test]
     fn stale_background_job_row_shows_no_output_warning_and_cancel_hint() {
         let mut app = create_test_app();
-        app.sidebar_focus = SidebarFocus::Tasks;
+        app.work_surface.panel = crate::tui::work_surface::RailPanel::Tasks;
         app.task_panel.push(TaskPanelEntry {
             id: "shell_stale".to_string(),
             status: "running".to_string(),
@@ -4548,7 +4541,7 @@ mod tests {
     #[test]
     fn task_panel_actions_route_each_job_to_its_own_id() {
         let mut app = create_test_app();
-        app.sidebar_focus = SidebarFocus::Tasks;
+        app.work_surface.panel = crate::tui::work_surface::RailPanel::Tasks;
         app.task_panel.push(TaskPanelEntry {
             id: "shell_aaa".to_string(),
             status: "running".to_string(),
@@ -4632,7 +4625,7 @@ mod tests {
     #[test]
     fn task_panel_finished_job_detail_row_shows_instead_of_cancels() {
         let mut app = create_test_app();
-        app.sidebar_focus = SidebarFocus::Tasks;
+        app.work_surface.panel = crate::tui::work_surface::RailPanel::Tasks;
         app.task_panel.push(TaskPanelEntry {
             id: "shell_done".to_string(),
             status: "completed".to_string(),
@@ -4669,7 +4662,7 @@ mod tests {
     #[test]
     fn task_panel_actions_align_with_lines_when_live_tools_present() {
         let mut app = create_test_app();
-        app.sidebar_focus = SidebarFocus::Tasks;
+        app.work_surface.panel = crate::tui::work_surface::RailPanel::Tasks;
         app.runtime_turn_id = Some("0196f0a3-aaaa-bbbb-cccc-ddddeeee0000".to_string());
         let mut active = ActiveCell::new();
         active.push_tool(
@@ -5133,7 +5126,7 @@ mod tests {
     #[test]
     fn tasks_panel_collapses_repeated_low_value_recent_tools_after_failures() {
         let mut app = create_test_app();
-        app.sidebar_focus = SidebarFocus::Tasks;
+        app.work_surface.panel = crate::tui::work_surface::RailPanel::Tasks;
         for path in ["src/a.rs", "src/b.rs", "src/c.rs"] {
             app.history
                 .push(HistoryCell::Tool(ToolCell::Generic(GenericToolCell {
@@ -5200,7 +5193,7 @@ mod tests {
     #[test]
     fn tasks_panel_collapses_repeated_pending_ci_polls() {
         let mut app = create_test_app();
-        app.sidebar_focus = SidebarFocus::Tasks;
+        app.work_surface.panel = crate::tui::work_surface::RailPanel::Tasks;
         for _ in 0..3 {
             app.history.push(HistoryCell::Tool(ToolCell::Exec(ExecCell {
                 command: "cd /tmp/repo && sleep 15 && gh pr checks 1616 --repo Hmbown/CodeWhale"
@@ -5248,7 +5241,7 @@ mod tests {
     #[test]
     fn tasks_panel_failed_shell_rows_point_to_activity_details() {
         let mut app = create_test_app();
-        app.sidebar_focus = SidebarFocus::Tasks;
+        app.work_surface.panel = crate::tui::work_surface::RailPanel::Tasks;
         app.history.push(HistoryCell::Tool(ToolCell::Exec(ExecCell {
             command: "cargo test -p codewhale-tui".to_string(),
             status: ToolStatus::Failed,
@@ -5282,7 +5275,7 @@ mod tests {
     #[test]
     fn tasks_panel_keeps_duration_and_status_on_recent_shell_rows() {
         let mut app = create_test_app();
-        app.sidebar_focus = SidebarFocus::Tasks;
+        app.work_surface.panel = crate::tui::work_surface::RailPanel::Tasks;
         app.history.push(HistoryCell::Tool(ToolCell::Exec(ExecCell {
             command: "cargo check".to_string(),
             status: ToolStatus::Success,
@@ -5314,7 +5307,7 @@ mod tests {
     #[test]
     fn tasks_panel_uses_plain_names_for_shell_background_helpers() {
         let mut app = create_test_app();
-        app.sidebar_focus = SidebarFocus::Tasks;
+        app.work_surface.panel = crate::tui::work_surface::RailPanel::Tasks;
         let mut active = ActiveCell::new();
         active.push_tool(
             "shell-wait",
@@ -5346,7 +5339,7 @@ mod tests {
     #[test]
     fn tasks_panel_collapses_repeated_shell_waits_for_same_job() {
         let mut app = create_test_app();
-        app.sidebar_focus = SidebarFocus::Tasks;
+        app.work_surface.panel = crate::tui::work_surface::RailPanel::Tasks;
         let mut active = ActiveCell::new();
         for id in ["shell-wait-1", "shell-wait-2"] {
             active.push_tool(
@@ -5383,7 +5376,7 @@ mod tests {
     #[test]
     fn tasks_panel_collapses_repeated_shell_waits_without_task_marker() {
         let mut app = create_test_app();
-        app.sidebar_focus = SidebarFocus::Tasks;
+        app.work_surface.panel = crate::tui::work_surface::RailPanel::Tasks;
         let mut active = ActiveCell::new();
         for (id, summary) in [
             ("shell-wait-1", "Background task running (no new output)."),
@@ -6418,7 +6411,7 @@ mod tests {
     #[test]
     fn tasks_panel_shows_stable_turn_label_not_uuid() {
         let mut app = create_test_app();
-        app.sidebar_focus = SidebarFocus::Tasks;
+        app.work_surface.panel = crate::tui::work_surface::RailPanel::Tasks;
         app.runtime_turn_id = Some("0196f0a3-1111-2222-3333-444455556666".to_string());
         app.runtime_turn_status = Some("in_progress".to_string());
         app.turn_counter = 3;
@@ -6443,7 +6436,7 @@ mod tests {
     #[test]
     fn tasks_panel_turn_label_falls_back_before_first_counted_turn() {
         let mut app = create_test_app();
-        app.sidebar_focus = SidebarFocus::Tasks;
+        app.work_surface.panel = crate::tui::work_surface::RailPanel::Tasks;
         app.runtime_turn_id = Some("0196f0a3-1111-2222-3333-444455556666".to_string());
         app.runtime_turn_status = Some("in_progress".to_string());
         app.turn_counter = 0;

crates/tui/src/tui/subagent_routing.rs

@@ -9,7 +9,7 @@ use crate::tools::subagent::{
 };
 use crate::tui::app::{
     AgentCurrentActivity, AgentCurrentActivityStatus, AgentProgressMeta, AgentRecentAction, App,
-    AppMode, MAX_AGENT_RECENT_ACTIONS, SidebarFocus, TaskPanelEntry, TaskPanelEntryKind,
+    AppMode, MAX_AGENT_RECENT_ACTIONS, TaskPanelEntry, TaskPanelEntryKind,
     bound_agent_activity_text,
 };
 use crate::tui::history::{HistoryCell, SubAgentCell, summarize_tool_output};
@@ -23,13 +23,6 @@ use crate::tui::workspace_context;
 const SUBAGENT_TERMINAL_CARD_TTL: Duration = Duration::from_secs(5 * 60);
 const SUBAGENT_TERMINAL_CARD_MAX_RETAINED: usize = 24;
 
-fn agents_panel_has_content(app: &App) -> bool {
-    !app.subagent_cache.is_empty()
-        || !app.agent_progress.is_empty()
-        || active_fanout_counts(app).is_some()
-        || foreground_rlm_running(app)
-}
-
 fn foreground_rlm_running(app: &App) -> bool {
     use crate::tui::history::{HistoryCell, ToolCell, ToolStatus};
     app.active_cell.as_ref().is_some_and(|active| {
@@ -46,14 +39,11 @@ fn foreground_rlm_running(app: &App) -> bool {
     })
 }
 
-/// True when the Agents sidebar panel is on-screen and already owns fanout summary.
+/// True when the rail's Agents panel is on-screen and already owns fanout
+/// summary, so the footer chip would be redundant.
 pub(super) fn agents_sidebar_surface_visible(app: &App) -> bool {
-    match app.sidebar_focus {
-        SidebarFocus::Hidden => false,
-        SidebarFocus::Agents => true,
-        SidebarFocus::Auto => agents_panel_has_content(app),
-        _ => false,
-    }
+    app.work_surface.panel == crate::tui::work_surface::RailPanel::Agents
+        && app.work_surface.last_area.is_some()
 }
 
 pub(super) fn running_agent_count(app: &App) -> usize {

crates/tui/src/tui/ui.rs

@@ -138,10 +138,10 @@ use super::key_actions;
 use super::app::{
     ActiveTurnMetadata, AgentCurrentActivity, AgentCurrentActivityStatus, App, AppAction, AppMode,
     ComposerSubmitAction, ComposerSubmitChord, EffectiveReasoningEffort, HuntVerdict,
-    OnboardingState, PendingProviderSwitch, QueuedMessage, ReasoningEffort, SidebarFocus,
-    StatusToast, StatusToastLevel, SubmitDisposition, TaskPanelEntry, TaskPanelEntryKind,
-    ToolEvidence, TuiOptions, bound_agent_activity_text, is_stop_word,
-    looks_like_slash_command_input, shell_command_from_bang_input,
+    OnboardingState, PendingProviderSwitch, QueuedMessage, ReasoningEffort, StatusToast,
+    StatusToastLevel, SubmitDisposition, TaskPanelEntry, TaskPanelEntryKind, ToolEvidence,
+    TuiOptions, bound_agent_activity_text, is_stop_word, looks_like_slash_command_input,
+    shell_command_from_bang_input,
 };
 use super::approval::{
     ApprovalMode, ApprovalRequest, ApprovalView, ElevationRequest, ElevationView, ReviewDecision,
@@ -13830,15 +13830,6 @@ fn render(f: &mut Frame, app: &mut App, _config: &Config) {
                 app.file_tree_visible = false;
                 work_chat_area
             };
-        app.last_sidebar_host_width = Some(chat_area.width);
-        // The legacy classic-shell sidebar no longer exists: no sidebar area
-        // is ever produced, so clear the interaction state its former mouse
-        // handlers read.
-        app.viewport.last_sidebar_area = None;
-        app.last_sidebar_area = None;
-        app.last_sidebar_handle_area = None;
-        app.sidebar_resizing = false;
-        app.sidebar_resize_hovered = false;
         app.sidebar_hover_tooltip = None;
 
         let chat_widget = ChatWidget::new(app, chat_area).with_ocean_viewport(size);

crates/tui/src/tui/ui/tests.rs

@@ -812,7 +812,7 @@ fn approval_mouse_wheel_reviews_transcript_without_closing_card() {
 }
 
 #[test]
-fn approval_wheel_preserves_sidebar_and_work_surface_ownership() {
+fn approval_wheel_preserves_work_surface_ownership() {
     let mut app = create_test_app();
     app.view_stack.push(ApprovalView::new(ApprovalRequest::new(
         "approval-scroll",
@@ -821,11 +821,10 @@ fn approval_wheel_preserves_sidebar_and_work_surface_ownership() {
         &serde_json::json!({"command": "git status"}),
         "approval-scroll-key",
     )));
-    app.viewport.last_sidebar_area = Some(Rect::new(60, 0, 20, 20));
     app.work_surface.last_area = Some(Rect::new(0, 0, 30, 20));
     app.viewport.last_approval_area = Some(Rect::new(0, 12, 80, 8));
 
-    for (column, row) in [(65, 4), (10, 4)] {
+    for (column, row) in [(10, 4), (20, 4)] {
         let events = handle_mouse_event(
             &mut app,
             MouseEvent {
@@ -1980,12 +1979,7 @@ fn loading_mouse_filter_keeps_hover_and_active_drags() {
     app.viewport.transcript_scrollbar_dragging = true;
     assert!(!should_drop_loading_mouse_motion(&app, drag));
 
-    // Sidebar drag-to-resize must also survive the loading filter (#3063).
     app.viewport.transcript_scrollbar_dragging = false;
-    app.sidebar_resizing = true;
-    assert!(!should_drop_loading_mouse_motion(&app, drag));
-
-    app.sidebar_resizing = false;
     app.work_surface.last_area = Some(Rect::new(0, 0, 80, 3));
     let started = crate::tui::work_surface::handle_mouse(
         &mut app,
@@ -2007,7 +2001,6 @@ fn loading_mouse_filter_keeps_hover_and_active_drags() {
 fn loading_mouse_filter_allows_sidebar_hover_to_clear() {
     let mut app = create_test_app();
     app.is_loading = true;
-    app.viewport.last_sidebar_area = Some(Rect::new(60, 4, 20, 6));
     app.sidebar_hover_tooltip = Some("Stale sidebar tooltip".to_string());
     let moved = MouseEvent {
         kind: MouseEventKind::Moved,
@@ -2027,7 +2020,6 @@ fn loading_mouse_filter_allows_sidebar_hover_to_clear() {
 fn loading_mouse_filter_allows_sidebar_exit_to_clear_highlight() {
     let mut app = create_test_app();
     app.is_loading = true;
-    app.viewport.last_sidebar_area = Some(Rect::new(60, 4, 20, 6));
     app.last_mouse_pos = Some((60, 5));
 
     let exit_left = MouseEvent {
@@ -8785,10 +8777,10 @@ fn hotbar_alt_digit_fires_from_composer_and_sidebar_states() {
     app.input = "   ".to_string();
     assert_eq!(hotbar_slot_from_key(&app, &alt_four), Some(4));
 
-    app.sidebar_focus = SidebarFocus::Hidden;
+    app.work_surface.placement = crate::tui::work_surface::WorkSurfacePlacement::Off;
     assert_eq!(hotbar_slot_from_key(&app, &alt_four), Some(4));
 
-    app.sidebar_focus = SidebarFocus::Agents;
+    app.work_surface.panel = crate::tui::work_surface::RailPanel::Agents;
     assert_eq!(hotbar_slot_from_key(&app, &alt_four), Some(4));
 }
 
@@ -9147,7 +9139,8 @@ fn ctrl_x_jobs_prefill_only_catches_running_shell_jobs_in_tasks_sidebar() {
 #[test]
 fn ctrl_x_jobs_prefill_falls_through_outside_tasks_sidebar_shell_jobs() {
     let mut non_shell = create_test_app();
-    non_shell.sidebar_focus = SidebarFocus::Tasks;
+    non_shell.work_surface.panel = crate::tui::work_surface::RailPanel::Tasks;
+    non_shell.work_surface.last_area = Some(ratatui::layout::Rect::new(0, 0, 100, 3));
     non_shell.input = "draft".to_string();
     non_shell.cursor_position = non_shell.input.len();
     non_shell.task_panel.push(TaskPanelEntry {