fix(desktop): session-tab drag, focus sync, and pop-out isolation

Make every session tab speak the same drag language as a sidebar row, and
keep tab focus 1:1 across the sidebar, tiles, and main:

- Drag a session tile's OR the main workspace tab onto a composer to link the
  chat (@session chip), or onto a zone/edge to stack/split — tabDrag now
  returns whether it took the drag, so the workspace tab defers to the generic
  pane move on a fresh draft (nothing to link).
- A lone tool panel (terminal/logs) dragged to its own zone keeps its header,
  so it stays draggable/closable instead of stranding a dead, tab-less zone.
- The sidebar highlight follows the FOCUSED session (interacted tile, else the
  main selection) rather than only the main one.
- Clicking an already-open session jumps to its tab — an open tile, or the
  workspace tab when it's the main session and focus sits on a tile — instead
  of a dead no-op reload.
- Secondary (single-chat pop-out) windows boot to the default tree with no
  tiles and never persist their stripped-down layout back, so they can't
  inherit or clobber the primary window's tabs/splits.

The pointer drag ghost is extracted to a shared lib/drag-ghost and the drop
affordances drop their now-unused labels.

apps/desktop/src/app/chat/chat-drop-overlay.tsx

@@ -1,39 +1,32 @@
 import { useRef } from 'react'
 
 import type { DragKind } from '@/app/chat/hooks/use-file-drop-zone'
-import { DROP_SHEET_BLUR_CLASS, DROP_SHEET_CLASS, DropPill } from '@/components/ui/drop-affordance'
+import { DROP_SHEET_BLUR_CLASS, DROP_SHEET_CLASS } from '@/components/ui/drop-affordance'
 import { useI18n } from '@/i18n'
 import { cn } from '@/lib/utils'
 
-const ICONS: Record<'files' | 'session', string> = {
-  files: 'cloud-upload',
-  session: 'comment-discussion'
-}
-
 /**
  * Full-bleed affordance shown while files or a session are dragged over the chat
  * area. Always `pointer-events-none` so the drop lands on the real element
  * underneath and the drop-zone handler claims it — the overlay is purely visual.
- * Copy adapts to whatever is being dragged; the last kind is held through the
- * fade-out so the label doesn't blank.
+ * The label names the outcome (attach files / link this chat); the last kind is
+ * held through the fade-out so it doesn't blank.
  */
 export function ChatDropOverlay({ kind }: { kind: DragKind }) {
   const { t } = useI18n()
-  const lastKind = useRef<'files' | 'session'>('files')
+  const lastKind = useRef<DragKind>(kind)
 
   if (kind) {
     lastKind.current = kind
   }
 
-  const resolvedKind = kind ?? lastKind.current
-  const icon = ICONS[resolvedKind]
-  const label = resolvedKind === 'files' ? t.composer.dropFiles : t.composer.dropSession
+  const shown = kind ?? lastKind.current
 
   return (
     <div
       aria-hidden
       className={cn(
-        'pointer-events-none absolute inset-0 z-40 flex items-center justify-center p-4 transition-opacity duration-150 ease-out',
+        'pointer-events-none absolute inset-0 z-40 flex items-center justify-center transition-opacity duration-150 ease-out',
         kind ? 'opacity-100' : 'opacity-0'
       )}
       data-slot="chat-drop-overlay"
@@ -45,9 +38,11 @@ export function ChatDropOverlay({ kind }: { kind: DragKind }) {
           'absolute inset-2 border-[color-mix(in_srgb,var(--dt-composer-ring)_55%,transparent)] bg-[color-mix(in_srgb,var(--dt-card)_55%,transparent)]'
         )}
       />
-      <DropPill className="relative" icon={icon}>
-        {label}
-      </DropPill>
+      {shown && (
+        <span className="relative text-[11px] font-medium uppercase tracking-wide text-foreground">
+          {shown === 'session' ? t.composer.dropSession : t.composer.dropFiles}
+        </span>
+      )}
     </div>
   )
 }

apps/desktop/src/app/chat/composer/inline-refs.ts

@@ -1,4 +1,5 @@
 import { formatRefValue } from '@/components/assistant-ui/directive-text'
+import { translateNow } from '@/i18n'
 import { contextPath } from '@/lib/chat-runtime'
 
 import type { DroppedFile } from '../hooks/use-composer-actions'
@@ -16,10 +17,14 @@ export interface SessionDragPayload {
   title: string
 }
 
+/** A session's friendly display label — its title, or a localized fallback. */
+export const sessionLabel = ({ id, title }: SessionDragPayload) =>
+  title || translateNow('sidebar.row.untitledChat', id.slice(0, 8))
+
 /** Build a `@session:<profile>/<id>` chip. Value carries the metadata the agent
  * needs to resolve the link (session_search); label shows the friendly title. */
-export function sessionInlineRef({ id, profile, title }: SessionDragPayload): InlineRefInput {
-  return { kind: 'session', label: title || `chat ${id.slice(0, 8)}`, value: `${profile || 'default'}/${id}` }
+export function sessionInlineRef(payload: SessionDragPayload): InlineRefInput {
+  return { kind: 'session', label: sessionLabel(payload), value: `${payload.profile || 'default'}/${payload.id}` }
 }
 
 export function dragHasAttachments(transfer: DataTransfer | null, pathsMime: string) {

apps/desktop/src/app/chat/hooks/use-file-drop-zone.ts

@@ -1,6 +1,7 @@
-import { type DragEvent as ReactDragEvent, useCallback, useRef, useState } from 'react'
+import { type DragEvent as ReactDragEvent, useCallback, useEffect, useRef, useState } from 'react'
 
 import { dragHasAttachments } from '@/app/chat/composer/inline-refs'
+import { ESCAPE_PRIORITY, pushEscapeLayer } from '@/lib/escape-layers'
 
 import { type DroppedFile, extractDroppedFiles, HERMES_PATHS_MIME } from './use-composer-actions'
 
@@ -27,16 +28,48 @@ interface FileDropZoneOptions {
  * `onDrop` would fire.
  *
  * Spread `dropHandlers` onto the container; render an overlay off `dragKind`.
+ * Esc aborts an in-flight drag, matching the sidebar session drag.
  */
 export function useFileDropZone({ enabled = true, onDropFiles }: FileDropZoneOptions) {
   const [dragKind, setDragKind] = useState<DragKind>(null)
   const depth = useRef(0)
+  const aborted = useRef(false)
 
   const reset = useCallback(() => {
     depth.current = 0
     setDragKind(null)
   }, [])
 
+  // Esc aborts a file drag — the same "never mind" a session drag gets. Native
+  // DnD can't be cancelled at the OS level, so we drop the overlay and arm a
+  // guard that swallows the trailing drop instead. Top escape layer + capture
+  // stop so it doesn't also fire a handler behind the drag (see drag-session).
+  useEffect(() => {
+    if (dragKind === null) {
+      return
+    }
+
+    const releaseLayer = pushEscapeLayer(ESCAPE_PRIORITY.drag)
+
+    const onKey = (event: KeyboardEvent) => {
+      if (event.key !== 'Escape') {
+        return
+      }
+
+      event.preventDefault()
+      event.stopPropagation()
+      aborted.current = true
+      reset()
+    }
+
+    window.addEventListener('keydown', onKey, true)
+
+    return () => {
+      window.removeEventListener('keydown', onKey, true)
+      releaseLayer()
+    }
+  }, [dragKind, reset])
+
   const onDragEnter = useCallback(
     (event: ReactDragEvent) => {
       const kind = enabled ? dragKindOf(event) : null
@@ -46,6 +79,12 @@ export function useFileDropZone({ enabled = true, onDropFiles }: FileDropZoneOpt
       }
 
       event.preventDefault()
+
+      // A genuinely new drag (not a nested-child re-enter) re-arms after abort.
+      if (depth.current === 0) {
+        aborted.current = false
+      }
+
       depth.current += 1
       setDragKind(kind)
     },
@@ -78,9 +117,12 @@ export function useFileDropZone({ enabled = true, onDropFiles }: FileDropZoneOpt
         return
       }
 
-      // An outer layer may have already claimed this drop via preventDefault —
-      // reset the hover state but don't ALSO act on it.
-      const claimed = event.defaultPrevented
+      // Only an Esc abort swallows the drop — NOT `event.defaultPrevented`. The
+      // file tree's app-wide react-dnd HTML5Backend preventDefaults every native
+      // file drop in the capture phase, so that flag is always set here (every
+      // Finder drop would no-op). Genuine nested targets claim via stopPropagation
+      // and never reach this bubble handler anyway.
+      const claimed = aborted.current
 
       event.preventDefault()
       reset()

apps/desktop/src/app/chat/pane-mirror.ts

@@ -7,8 +7,9 @@
  */
 
 import type { ReadableAtom } from 'nanostores'
-import type { ReactElement, ReactNode } from 'react'
+import type { ReactElement, ReactNode, PointerEvent as ReactPointerEvent } from 'react'
 
+import type { DoubleTapContext } from '@/components/pane-shell/tree/renderer/drag-session'
 import { registerPaneCloser, removeTreePane, treePanesWithPrefix } from '@/components/pane-shell/tree/store'
 import { registry } from '@/contrib/registry'
 import type { TileDock } from '@/store/session-states'
@@ -33,6 +34,14 @@ export interface PaneMirror<T> {
   render: (key: string) => ReactNode
   /** Wrap the tile's TAB (domain context menu — session verbs). */
   tabWrap?: (key: string, tab: ReactElement) => ReactNode
+  /** Override the tile's TAB drag (session drop language: stack/split/link).
+   *  Returns whether it took the drag (see PaneChrome.tabDrag). */
+  tabDrag?: (
+    key: string,
+    event: ReactPointerEvent<HTMLElement>,
+    onTap: () => void,
+    double?: DoubleTapContext
+  ) => boolean
   /** Wired as the pane's closer (tab Close). */
   close: (key: string) => void
 }
@@ -62,9 +71,17 @@ export function paneMirror<T>(cfg: PaneMirror<T>): () => void {
         area: 'panes',
         title,
         data: {
-          dock: { before: cfg.before?.(tile), pane: cfg.anchor?.(tile) ?? 'workspace', pos: cfg.dir?.(tile) ?? 'right' },
+          dock: {
+            before: cfg.before?.(tile),
+            pane: cfg.anchor?.(tile) ?? 'workspace',
+            pos: cfg.dir?.(tile) ?? 'right'
+          },
           minWidth: cfg.minWidth,
           placement: 'main',
+          tabDrag: cfg.tabDrag
+            ? (event: ReactPointerEvent<HTMLElement>, onTap: () => void, double?: DoubleTapContext) =>
+                cfg.tabDrag!(key, event, onTap, double)
+            : undefined, // returns boolean (handled) — see PaneChrome.tabDrag
           tabWrap: cfg.tabWrap ? (tab: ReactElement) => cfg.tabWrap!(key, tab) : undefined
         },
         render: () => cfg.render(key)

apps/desktop/src/app/chat/session-drag.ts

@@ -29,6 +29,7 @@ import type { PointerEvent as ReactPointerEvent } from 'react'
 
 import { findGroup } from '@/components/pane-shell/tree/model'
 import {
+  type DoubleTapContext,
   rectContains,
   slotBefore,
   snapshotStrips,
@@ -37,12 +38,18 @@ import {
   type StripSnapshot,
   subZonePosition
 } from '@/components/pane-shell/tree/renderer/drag-session'
-import { $layoutTree, $treeDragging, type DropHint, revealTreePane, SESSION_TILE_DRAG } from '@/components/pane-shell/tree/store'
+import {
+  $layoutTree,
+  $treeDragging,
+  type DropHint,
+  revealTreePane,
+  SESSION_TILE_DRAG
+} from '@/components/pane-shell/tree/store'
 import type { EngineZone, ZoneRect } from '@/components/pane-shell/tree/zones-engine'
 import { openSessionTile, type TileDock } from '@/store/session-states'
 
 import { requestComposerInsertRefs } from './composer/focus'
-import { type SessionDragPayload, sessionInlineRef } from './composer/inline-refs'
+import { type SessionDragPayload, sessionInlineRef, sessionLabel } from './composer/inline-refs'
 
 /** A chat surface's drag-start geometry: the anchor pane id it advertises
  *  (`data-session-anchor`) and the composer a link drop routes to
@@ -77,12 +84,18 @@ function chatZonePane(groupId: string): null | string {
 }
 
 /**
- * Begin dragging a sidebar session row. Sub-threshold releases stay ordinary
- * clicks (resume / pin / open-in-window all live on the row's own handlers);
- * past the threshold the row is a drag source and the release commits a
- * stack, a split, or a composer link — Esc aborts instantly.
+ * Begin dragging a session — a sidebar row OR a tile's own tab (same drop
+ * language either way: stack, split, or composer link). Sub-threshold releases
+ * stay ordinary clicks, so `opts.onTap` (activate the tile) and `opts.double`
+ * (hide the tab bar) ride the tab's gestures; Esc aborts instantly. A stack/
+ * split commits through `openSessionTile`, which OPENS a new tile from a sidebar
+ * row and MOVES the existing one when its tab is the drag source.
  */
-export function startSessionDrag(payload: SessionDragPayload, e: ReactPointerEvent<HTMLElement>) {
+export function startSessionDrag(
+  payload: SessionDragPayload,
+  e: ReactPointerEvent<HTMLElement>,
+  opts?: { double?: DoubleTapContext; onTap?: () => void }
+) {
   let zones: EngineZone[] = []
   let strips: StripSnapshot[] = []
   let surfaces: SurfaceSnapshot[] = []
@@ -94,8 +107,17 @@ export function startSessionDrag(payload: SessionDragPayload, e: ReactPointerEve
   let split: { anchor: string; before?: null | string; pos: TileDock } | null = null
   let link: null | string = null
 
+  // The drag SOURCE (sidebar row or tile tab). Captured synchronously — React
+  // clears `currentTarget` after the pointerdown handler returns, but this runs
+  // inside it. Dimmed while lifted so the source reads as "picked up" — the
+  // same in-place feedback pane-tab drags use, replacing the old cursor chip.
+  const source = e.currentTarget
+  const restoreOpacity = source?.style.opacity ?? ''
+
   startDragSession(e, {
-    ghost: { label: payload.title || `chat ${payload.id.slice(0, 8)}` },
+    double: opts?.double,
+    ghost: { label: sessionLabel(payload) },
+    onTap: opts?.onTap,
 
     onEngage() {
       zones = snapshotZones()
@@ -103,11 +125,18 @@ export function startSessionDrag(payload: SessionDragPayload, e: ReactPointerEve
       surfaces = snapshotSurfaces()
       composers = [...document.querySelectorAll<HTMLElement>('[data-slot="composer-root"]')].map(snapRect)
       zoneHost = new Map(zones.map(zone => [zone.id, chatZonePane(zone.id)]))
+      source?.style.setProperty('opacity', '0.45')
       // The same sentinel the zone overlay + chat surfaces key off — the
       // whole drop language (sheets, pills, caret, link overlay) lights up.
       $treeDragging.set(SESSION_TILE_DRAG)
     },
 
+    onEnd() {
+      if (source) {
+        source.style.opacity = restoreOpacity
+      }
+    },
+
     resolveMove(x, y): DropHint | null {
       const zone = zones.find(z => rectContains(z.rect, x, y))
       const host = zone ? zoneHost.get(zone.id) : null
@@ -123,7 +152,9 @@ export function startSessionDrag(payload: SessionDragPayload, e: ReactPointerEve
       const strip = strips.find(s => s.groupId === zone.id && rectContains(s.rect, x, y))
 
       if (strip) {
-        const stack = slotBefore(strip.slots, x)
+        // Exclude the tile's OWN tab from the slots so re-dropping it in its
+        // home strip reorders cleanly (a no-op for a sidebar-row drag).
+        const stack = slotBefore(strip.slots, x, `session-tile:${payload.id}`)
         split = { anchor: host, before: stack.before, pos: 'center' }
         link = null
 

apps/desktop/src/app/chat/session-tile.tsx

@@ -50,9 +50,11 @@ import {
   sessionTileDelegate
 } from '@/store/session-states'
 
+import type { SessionDragPayload } from './composer/inline-refs'
 import { type ComposerScope, ComposerScopeProvider } from './composer/scope'
 import { useComposerActions } from './hooks/use-composer-actions'
 import { paneMirror } from './pane-mirror'
+import { startSessionDrag } from './session-drag'
 import { useSessionTileActions } from './session-tile-actions'
 import { type SessionView, SessionViewProvider } from './session-view'
 import { SessionContextMenu } from './sidebar/session-actions-menu'
@@ -255,6 +257,13 @@ function tileTitle(storedSessionId: string): string {
   return stored ? sessionTitle(stored) : 'Session'
 }
 
+/** The `@session` link payload for a tile tab drag — id + owning profile + title. */
+function tileDragPayload(storedSessionId: string): SessionDragPayload {
+  const stored = $sessions.get().find(s => sessionMatchesStoredId(s, storedSessionId))
+
+  return { id: storedSessionId, profile: stored?.profile ?? '', title: tileTitle(storedSessionId) }
+}
+
 // ---------------------------------------------------------------------------
 // Close confirmation — a BUSY tab (streaming, or blocked on clarify/approval
 // input) doesn't close silently.
@@ -416,5 +425,12 @@ export const watchSessionTiles = paneMirror<SessionTile>({
       {tab}
     </SessionTabMenu>
   ),
+  // A tile's tab drags like a sidebar row — stack / split / drop-to-link — with
+  // its tap (activate) + double-tap (hide bar) preserved. Always takes the drag.
+  tabDrag: (storedSessionId, event, onTap, double) => {
+    startSessionDrag(tileDragPayload(storedSessionId), event, { double, onTap })
+
+    return true
+  },
   close: requestCloseSessionTile
 })

apps/desktop/src/app/chat/sidebar/index.tsx

@@ -87,7 +87,6 @@ import {
   $messagingPlatformTotals,
   $messagingSessions,
   $messagingTruncated,
-  $selectedStoredSessionId,
   $sessionProfileTotals,
   $sessions,
   $sessionsLoading,
@@ -96,7 +95,7 @@ import {
   sessionPinId,
   setCurrentCwd
 } from '@/store/session'
-import type { SplitDir } from '@/store/session-states'
+import { $focusedStoredSessionId, type SplitDir } from '@/store/session-states'
 
 import {
   type AppView,
@@ -277,7 +276,9 @@ export function ChatSidebar({
   const pinsOpen = useStore($sidebarPinsOpen)
   const agentsOpen = useStore($sidebarRecentsOpen)
   const cronOpen = useStore($sidebarCronOpen)
-  const selectedSessionId = useStore($selectedStoredSessionId)
+  // The sidebar highlight tracks the FOCUSED session — the interacted tile's
+  // tab, else the main selection — so it stays 1:1 with whatever tab is active.
+  const selectedSessionId = useStore($focusedStoredSessionId)
   const sessions = useStore($sessions)
   const cronSessions = useStore($cronSessions)
   const cronJobs = useStore($cronJobs)
@@ -1095,46 +1096,46 @@ export function ChatSidebar({
                 const isNewSession = item.id === 'new-session'
 
                 const button = (
-                    <SidebarMenuButton
-                      aria-disabled={!isInteractive}
-                      className={cn(
-                        // no-drag: these rows sit directly under the titlebar's
-                        // [-webkit-app-region:drag] strips (app-shell.tsx), with only
-                        // 6px of clearance. Drag regions win hit-testing over DOM
-                        // (pointer-events can't override), and on Linux/WSLg the
-                        // resolved region has been observed to swallow clicks on the
-                        // top rows. Same carve-out as USER_BUBBLE_BASE_CLASS in
-                        // thread.tsx.
-                        'flex h-7 w-full justify-start gap-2 rounded-md border border-transparent px-2 text-left text-[0.8125rem] font-medium text-(--ui-text-secondary) transition-colors duration-100 ease-out [-webkit-app-region:no-drag] hover:bg-(--ui-control-hover-background) hover:text-foreground hover:transition-none',
-                        active &&
-                          'border-(--ui-stroke-tertiary) bg-(--ui-control-active-background) text-foreground shadow-none hover:border-(--ui-stroke-tertiary)!',
-                        !isInteractive &&
-                          'cursor-default hover:border-transparent hover:bg-transparent hover:text-inherit'
-                      )}
-                      onClick={() => {
-                        // A plain new session lands in whatever profile the live
-                        // gateway is on (= the active switcher context). null →
-                        // no swap. The switcher header is the single place to
-                        // change which profile that is.
-                        if (isNewSession) {
-                          $newChatProfile.set(null)
-                        }
+                  <SidebarMenuButton
+                    aria-disabled={!isInteractive}
+                    className={cn(
+                      // no-drag: these rows sit directly under the titlebar's
+                      // [-webkit-app-region:drag] strips (app-shell.tsx), with only
+                      // 6px of clearance. Drag regions win hit-testing over DOM
+                      // (pointer-events can't override), and on Linux/WSLg the
+                      // resolved region has been observed to swallow clicks on the
+                      // top rows. Same carve-out as USER_BUBBLE_BASE_CLASS in
+                      // thread.tsx.
+                      'flex h-7 w-full justify-start gap-2 rounded-md border border-transparent px-2 text-left text-[0.8125rem] font-medium text-(--ui-text-secondary) transition-colors duration-100 ease-out [-webkit-app-region:no-drag] hover:bg-(--ui-control-hover-background) hover:text-foreground hover:transition-none',
+                      active &&
+                        'border-(--ui-stroke-tertiary) bg-(--ui-control-active-background) text-foreground shadow-none hover:border-(--ui-stroke-tertiary)!',
+                      !isInteractive &&
+                        'cursor-default hover:border-transparent hover:bg-transparent hover:text-inherit'
+                    )}
+                    onClick={() => {
+                      // A plain new session lands in whatever profile the live
+                      // gateway is on (= the active switcher context). null →
+                      // no swap. The switcher header is the single place to
+                      // change which profile that is.
+                      if (isNewSession) {
+                        $newChatProfile.set(null)
+                      }
 
-                        onNavigate(item)
-                      }}
-                      tooltip={s.nav[item.id] ?? item.label}
-                      type="button"
-                    >
-                      <item.icon className="size-4 shrink-0 text-[color-mix(in_srgb,currentColor_72%,transparent)]" />
-                      <span className="min-w-0 flex-1 truncate">{s.nav[item.id] ?? item.label}</span>
-                      {isNewSession && (
-                        <KbdGroup
-                          className={cn('ml-auto opacity-55', newSessionKbdFlash && 'opacity-100!')}
-                          keys={[...NEW_SESSION_KBD]}
-                          size="sm"
-                        />
-                      )}
-                    </SidebarMenuButton>
+                      onNavigate(item)
+                    }}
+                    tooltip={s.nav[item.id] ?? item.label}
+                    type="button"
+                  >
+                    <item.icon className="size-4 shrink-0 text-[color-mix(in_srgb,currentColor_72%,transparent)]" />
+                    <span className="min-w-0 flex-1 truncate">{s.nav[item.id] ?? item.label}</span>
+                    {isNewSession && (
+                      <KbdGroup
+                        className={cn('ml-auto opacity-55', newSessionKbdFlash && 'opacity-100!')}
+                        keys={[...NEW_SESSION_KBD]}
+                        size="sm"
+                      />
+                    )}
+                  </SidebarMenuButton>
                 )
 
                 // New session + route-backed pages can open in a split —

apps/desktop/src/app/contrib/controller.tsx

@@ -1,6 +1,6 @@
 import { useStore } from '@nanostores/react'
 import { computed } from 'nanostores'
-import type { CSSProperties, ReactElement } from 'react'
+import type { CSSProperties, ReactElement, PointerEvent as ReactPointerEvent } from 'react'
 
 import { PREVIEW_RAIL_MAX_WIDTH, PREVIEW_RAIL_MIN_WIDTH } from '@/app/chat/right-rail'
 import { PALETTE_AREA, type PaletteContribution } from '@/app/command-palette/contrib'
@@ -8,6 +8,7 @@ import { type StatusbarItem } from '@/app/shell/statusbar-controls'
 import { toggleLayoutEditMode } from '@/components/pane-shell/edit-mode'
 import { allPaneIds, group, split } from '@/components/pane-shell/tree/model'
 import { LayoutTreeRoot } from '@/components/pane-shell/tree/renderer'
+import type { DoubleTapContext } from '@/components/pane-shell/tree/renderer/drag-session'
 import {
   $layoutTree,
   bindTreeSideVisibility,
@@ -52,7 +53,9 @@ import { $filePreviewTarget, $previewTarget, closeRightRail } from '@/store/prev
 import { $reviewOpen, closeReview, REVIEW_PANE_ID } from '@/store/review'
 import { $currentCwd, $selectedStoredSessionId, $sessions, sessionMatchesStoredId } from '@/store/session'
 
+import type { SessionDragPayload } from '../chat/composer/inline-refs'
 import { watchRouteTiles } from '../chat/route-tile'
+import { startSessionDrag } from '../chat/session-drag'
 import {
   SessionTileCloseConfirm,
   stackSessionTilesIntoMain,
@@ -91,6 +94,35 @@ const renderWorkspacePane = () => <WiredPane part="chatRoutes" />
 // the loaded primary session; no menu on a fresh draft).
 const wrapWorkspaceTab = (tab: ReactElement) => <WorkspaceTabMenu>{tab}</WorkspaceTabMenu>
 
+/** The `@session` payload for the workspace tab — the loaded primary session,
+ *  or null on a fresh draft / full-page view (nothing to link). */
+const workspaceDragPayload = (): SessionDragPayload | null => {
+  const selected = $selectedStoredSessionId.get()
+
+  if (!selected || $workspaceIsPage.get()) {
+    return null
+  }
+
+  const stored = $sessions.get().find(s => sessionMatchesStoredId(s, selected))
+
+  return { id: selected, profile: stored?.profile ?? '', title: stored ? storedSessionTitle(stored) : '' }
+}
+
+// The main tab drags like a session tile — drop it on a composer to link the
+// chat, on a zone/edge to stack/split. Defers (`false`) to the generic pane
+// move when there's no loaded session to carry.
+const workspaceTabDrag = (event: ReactPointerEvent<HTMLElement>, onTap: () => void, double?: DoubleTapContext) => {
+  const payload = workspaceDragPayload()
+
+  if (!payload) {
+    return false
+  }
+
+  startSessionDrag(payload, event, { double, onTap })
+
+  return true
+}
+
 registry.registerMany([
   {
     id: 'sessions',
@@ -115,7 +147,13 @@ registry.registerMany([
     area: 'panes',
     // Live-retitled to the loaded session by syncWorkspaceTitle below.
     title: 'New session',
-    data: { placement: 'main', minWidth: '22vw', tabWrap: wrapWorkspaceTab, uncloseable: true },
+    data: {
+      placement: 'main',
+      minWidth: '22vw',
+      tabDrag: workspaceTabDrag,
+      tabWrap: wrapWorkspaceTab,
+      uncloseable: true
+    },
     render: renderWorkspacePane
   },
   {
@@ -370,6 +408,7 @@ const syncWorkspaceTitle = () => {
       headerVeto: $workspaceIsPage.get(),
       placement: 'main',
       minWidth: '22vw',
+      tabDrag: workspaceTabDrag,
       tabWrap: wrapWorkspaceTab,
       uncloseable: true
     },

apps/desktop/src/app/contrib/wiring.tsx

@@ -54,6 +54,7 @@ import {
   setCurrentProvider,
   setMessages
 } from '@/store/session'
+import { focusOpenSession } from '@/store/session-states'
 import { clearSessionTodos, setSessionTodos, todosForHydration } from '@/store/todos'
 import { isSecondaryWindow } from '@/store/windows'
 import { useSkinCommand } from '@/themes/use-skin-command'
@@ -716,7 +717,13 @@ export function ContribWiring({ children }: { children: ReactNode }) {
     onReload: reloadFromMessage,
     onRemoveAttachment: id => void composer.removeAttachment(id),
     onRestoreToMessage: restoreToMessage,
-    onResumeSession: sessionId => navigate(sessionRoute(sessionId)),
+    // Already on screen (open tile, or the main session)? Jump to its tab;
+    // otherwise load it into main.
+    onResumeSession: sessionId => {
+      if (!focusOpenSession(sessionId)) {
+        navigate(sessionRoute(sessionId))
+      }
+    },
     onRetryResume: sessionId => void resumeSession(sessionId, true),
     onSteer: steerPrompt,
     onSubmit: submitText,

apps/desktop/src/components/pane-shell/tree/model.ts

@@ -220,7 +220,10 @@ export function insertAtGroup(
   pos: DropPosition,
   /** Center drops only: stack BEFORE this pane id (`null`/omitted = append) —
    *  the tab-strip insertion divider's slot. */
-  before?: null | string
+  before?: null | string,
+  /** Front the inserted pane — TRUE for a gesture (drop/reveal), FALSE for silent
+   *  adoption (logs stacking into the terminal zone must not steal its tab). */
+  activate: boolean = true
 ): LayoutNode | null {
   const walk = (n: LayoutNode): LayoutNode => {
     if (n.type === 'group') {
@@ -236,8 +239,11 @@ export function insertAtGroup(
         // a stack you can't see is a trap, and once a zone has ever stacked
         // the bar STAYS when it drops back to one tab — the auto-hide flicker
         // while dragging tabs around felt broken. Hiding is the user's call
-        // (double-click / zone menu).
-        return { ...n, panes, active: paneId, headerHidden: false }
+        // (double-click / zone menu). Active moves only on a gesture; an empty
+        // target has no prior tab, so the newcomer takes it regardless.
+        const active = activate || n.panes.length === 0 ? paneId : n.active
+
+        return { ...n, panes, active, headerHidden: false }
       }
 
       const orientation: Orientation = pos === 'left' || pos === 'right' ? 'row' : 'column'
@@ -385,9 +391,7 @@ export function adjacentGroup(
 
     const index = parent.children.indexOf(path[i + 1])
 
-    const siblings = forward
-      ? parent.children.slice(index + 1)
-      : parent.children.slice(0, index).reverse()
+    const siblings = forward ? parent.children.slice(index + 1) : parent.children.slice(0, index).reverse()
 
     for (const sibling of siblings) {
       const hit = edgeGroup(sibling, OPPOSITE_EDGE[side], viable)

apps/desktop/src/components/pane-shell/tree/renderer/drag-session.ts

@@ -30,6 +30,7 @@
 
 import type { PointerEvent as ReactPointerEvent } from 'react'
 
+import { createDragGhost, type DragGhost } from '@/lib/drag-ghost'
 import { ESCAPE_PRIORITY, pushEscapeLayer } from '@/lib/escape-layers'
 import { reorderCommitHaptic, reorderStepHaptic } from '@/lib/reorder'
 
@@ -71,7 +72,7 @@ export function radialPosition(
     return 'center'
   }
 
-  return Math.abs(dx) >= Math.abs(dy) ? (dx < 0 ? 'left' : 'right') : (dy < 0 ? 'top' : 'bottom')
+  return Math.abs(dx) >= Math.abs(dy) ? (dx < 0 ? 'left' : 'right') : dy < 0 ? 'top' : 'bottom'
 }
 
 /** Sub-zone drop position within the zone `groupId` (radial hit-testing). */
@@ -177,28 +178,11 @@ export interface DragSessionSpec {
   onTap?(): void
   double?: DoubleTapContext
   /** Floating chip following the pointer — for drags whose source doesn't
-   *  stay visibly "held" (a sidebar row, unlike a dimmed tab). */
+   *  stay visibly "held" (a sidebar row, unlike a dimmed tab). See
+   *  `@/lib/drag-ghost`. */
   ghost?: { label: string }
 }
 
-/** The engaged drag's ghost chip: plain DOM (no React), themed via the same
- *  tokens as DropPill, moved with a transform — trivially cheap, and removal
- *  on Esc is synchronous. */
-function createGhost(label: string): HTMLElement {
-  const ghost = document.createElement('div')
-
-  ghost.textContent = label
-  ghost.style.cssText =
-    'position:fixed;left:0;top:0;z-index:9999;pointer-events:none;max-width:16rem;overflow:hidden;' +
-    'text-overflow:ellipsis;white-space:nowrap;padding:0.25rem 0.75rem;border-radius:9999px;' +
-    'border:1px solid color-mix(in srgb,var(--dt-composer-ring) 45%,transparent);' +
-    'background:color-mix(in srgb,var(--dt-card) 92%,transparent);color:var(--ui-text-primary);' +
-    'font-size:0.75rem;font-weight:500;box-shadow:0 4px 16px rgba(0,0,0,0.25);will-change:transform'
-  document.body.appendChild(ghost)
-
-  return ghost
-}
-
 /** After an ENGAGED drag, the release still synthesizes a `click` on the
  *  capture element — swallow exactly that one so a drag can never double as
  *  an activation (row resume, tab close). Committed drags see the click in
@@ -242,7 +226,7 @@ export function startDragSession(e: ReactPointerEvent<HTMLElement>, spec: DragSe
   const restoreSelect = document.body.style.userSelect
   let engaged = false
   let releaseEscapeLayer: (() => void) | null = null
-  let ghost: HTMLElement | null = null
+  let ghost: DragGhost | null = null
   let cursor: string | null = null
   // rAF-coalesced move processing: the raw handler only records the latest
   // point; all hit testing happens at most once per frame.
@@ -287,7 +271,7 @@ export function startDragSession(e: ReactPointerEvent<HTMLElement>, spec: DragSe
     releaseEscapeLayer = pushEscapeLayer(ESCAPE_PRIORITY.drag)
 
     if (spec.ghost) {
-      ghost = createGhost(spec.ghost.label)
+      ghost = createDragGhost(spec.ghost.label)
     }
 
     spec.onEngage(x, y)
@@ -302,9 +286,7 @@ export function startDragSession(e: ReactPointerEvent<HTMLElement>, spec: DragSe
       engage(x, y)
     }
 
-    if (ghost) {
-      ghost.style.transform = `translate3d(${x + 14}px, ${y + 12}px, 0)`
-    }
+    ghost?.moveTo(x, y)
 
     const hint = spec.resolveMove(x, y, shift)
 
@@ -344,7 +326,7 @@ export function startDragSession(e: ReactPointerEvent<HTMLElement>, spec: DragSe
 
     document.body.style.cursor = restoreCursor
     document.body.style.userSelect = restoreSelect
-    ghost?.remove()
+    ghost?.destroy()
     ghost = null
     releaseEscapeLayer?.()
     releaseEscapeLayer = null
@@ -428,13 +410,19 @@ const TEAR_OFF_SLACK_PX = 18
  * light up, the target's tab strip stacks at its divider slot, Shift extends
  * the highlight range, release drops into the ClosestCenter primary zone.
  * Esc aborts either mode.
+ *
+ * `ghostLabel` opts into the pointer-following chip (`@/lib/drag-ghost`) — the
+ * same "what am I holding" affordance sessions use. The in-strip dim only
+ * marks a tab; a header/edit-body drag or a torn-off tab has no held source
+ * near the pointer, so the chip carries the pane title along with it.
  */
 export function startPaneDrag(
   paneId: string,
   e: ReactPointerEvent<HTMLElement>,
   onTap?: () => void,
   reorder?: ReorderContext,
-  double?: DoubleTapContext
+  double?: DoubleTapContext,
+  ghostLabel?: string
 ) {
   if (e.button !== 0) {
     return
@@ -486,6 +474,7 @@ export function startPaneDrag(
 
   startDragSession(e, {
     double,
+    ghost: ghostLabel ? { label: ghostLabel } : undefined,
     onTap,
 
     onEngage(x, y) {

apps/desktop/src/components/pane-shell/tree/renderer/track-model.ts

@@ -14,6 +14,8 @@ import type { Contribution } from '@/contrib/types'
 import type { GroupNode, LayoutNode } from '../model'
 import { allPaneIds } from '../model'
 
+import type { DoubleTapContext } from './drag-session'
+
 export const MIN_PANE_PX = 80
 
 /** Optional CSS sizing a pane contributes (`data.width` / `data.minWidth`…).
@@ -46,6 +48,12 @@ interface PaneChrome {
    *  pin/branch/rename/archive/delete). The wrapper must render `tab` as its
    *  interactive child; the zone's own strip menu still owns non-tab space. */
   tabWrap?: (tab: React.ReactElement) => React.ReactNode
+  /** Override this pane's TAB drag (a session tab drags like a sidebar row —
+   *  stack / split / composer-link — not the generic pane move). Given the
+   *  tab's tap (activate) + double-tap (hide header) so those gestures survive.
+   *  Returns whether it took the drag; `false` (or absent) defers to
+   *  `startPaneDrag` — e.g. the workspace tab on a fresh draft, nothing to link. */
+  tabDrag?: (event: React.PointerEvent<HTMLElement>, onTap: () => void, double?: DoubleTapContext) => boolean
   /** Suppress the zone header while THIS pane is active — full-page views
    *  (artifacts/skills/plugin pages) are not tab-able surfaces. The flag is
    *  live: the workspace contribution re-registers it on route changes. */

apps/desktop/src/components/pane-shell/tree/renderer/tree-group.tsx

@@ -15,8 +15,14 @@ import { type CSSProperties, Fragment, type ReactNode, type RefObject, useRef, u
 import { Codicon } from '@/components/ui/codicon'
 import { ContextMenu, ContextMenuContent, ContextMenuItem, ContextMenuTrigger } from '@/components/ui/context-menu'
 import { DecodeText } from '@/components/ui/decode-text'
-import { DROP_SHEET_BLUR_CLASS, DROP_SHEET_CLASS, DropPill } from '@/components/ui/drop-affordance'
-import { PANE_TAB_STRIP_LINE, PANE_TAB_STRIP_LINE_LEFT, PANE_TAB_STRIP_LINE_RIGHT, PaneTab, PaneTabLabel } from '@/components/ui/pane-tab'
+import { DROP_SHEET_BLUR_CLASS, DROP_SHEET_CLASS } from '@/components/ui/drop-affordance'
+import {
+  PANE_TAB_STRIP_LINE,
+  PANE_TAB_STRIP_LINE_LEFT,
+  PANE_TAB_STRIP_LINE_RIGHT,
+  PaneTab,
+  PaneTabLabel
+} from '@/components/ui/pane-tab'
 import { ContribBoundary } from '@/contrib/react/boundary'
 import { useContributions } from '@/contrib/react/use-contributions'
 import { useI18n } from '@/i18n'
@@ -173,21 +179,25 @@ export function TreeGroup({
 
   // ONE header style: the app's compact pane-header. DEFAULT is contextual —
   // a single pane isn't a "tab", so its header auto-hides; a stack shows its
-  // chips. EXCEPTION: a lone TILE (closeable, placement 'main' — a session/page
-  // split) always shows its header, so it has a tab + close X — a tile in its
-  // own zone was otherwise unclosable (the "3rd tile has no tab" trap). Chrome
-  // panes (sessions/files/terminal…) and the uncloseable workspace keep the
-  // clean no-tab default. Double-click toggles it either way; a minimized
-  // group always shows its header (it IS the header).
-  const hasLoneTile = shown.some(id => {
-    const chrome = paneChrome(paneFor(id))
+  // chips. EXCEPTIONS force a lone pane to keep its header (tab + close X):
+  //  - a TILE (closeable, placement 'main' — a session/page split), else a
+  //    tile in its own zone is unclosable (the "3rd tile has no tab" trap);
+  //  - a TOOL PANEL (terminal/logs — a collapse pane) dragged out of the main
+  //    stack, else it's a dead zone with no tab to grab or ✕ to close.
+  // The uncloseable workspace and side chrome (sessions/files) keep the clean
+  // no-tab default. Double-click toggles it either way; a minimized group
+  // always shows its header (it IS the header).
+  const forceLoneHeader =
+    shown.some(id => {
+      const chrome = paneChrome(paneFor(id))
 
-    return !chrome.uncloseable && chrome.placement === 'main'
-  })
+      return !chrome.uncloseable && chrome.placement === 'main'
+    }) ||
+    (shown.length === 1 && isCollapsePane(shown[0]))
 
   // A full-page view (headerVeto) suppresses the strip while it's the active
   // pane — a page is not a tab-able surface; the bar returns with the chat.
-  const headerHidden = paneChrome(active).headerVeto || (node.headerHidden ?? (shown.length <= 1 && !hasLoneTile))
+  const headerHidden = paneChrome(active).headerVeto || (node.headerHidden ?? (shown.length <= 1 && !forceLoneHeader))
 
   // A group collapses ALONG its parent split's axis. In a row that means the
   // WIDTH collapses — a full-width horizontal header would strand a tall
@@ -362,7 +372,9 @@ export function TreeGroup({
             )}
             data-zone-tabstrip={node.id}
             onContextMenu={e => {
-              setMenuPane((e.target as HTMLElement).closest('[data-tree-tab]')?.getAttribute('data-tree-tab') ?? undefined)
+              setMenuPane(
+                (e.target as HTMLElement).closest('[data-tree-tab]')?.getAttribute('data-tree-tab') ?? undefined
+              )
             }}
             onPointerDown={e =>
               // Tap the header to collapse to it / expand back — the DetailPane
@@ -373,7 +385,8 @@ export function TreeGroup({
                 e,
                 () => minimizable && toggleCollapse(),
                 undefined,
-                hideHeaderDoubleTap
+                hideHeaderDoubleTap,
+                active?.title ?? activeId
               )
             }
             ref={stripRef}
@@ -396,25 +409,43 @@ export function TreeGroup({
                     data-tree-tab={paneId}
                     key={paneId}
                     onClose={closeable ? () => closeTab(paneId) : undefined}
-                    onPointerDown={e =>
-                      startPaneDrag(
-                        paneId,
-                        e,
-                        () => {
-                          // Tabs ACTIVATE (restoring a collapsed group).
-                          // Minimize lives on the chevron / single-pane label
-                          // — overloading the active tab made double-click a
-                          // minimize/restore/hide lottery.
-                          if (node.minimized) {
-                            restoreTreePane(paneId)
-                          }
+                    onPointerDown={e => {
+                      // Tabs ACTIVATE (restoring a collapsed group). Minimize
+                      // lives on the chevron / single-pane label — overloading
+                      // the active tab made double-click a minimize/restore/hide
+                      // lottery.
+                      const onTap = () => {
+                        if (node.minimized) {
+                          restoreTreePane(paneId)
+                        }
 
-                          activateTreePane(node.id, paneId)
-                        },
-                        stripRef.current ? { groupId: node.id, strip: stripRef.current } : undefined,
-                        hideHeaderDoubleTap
-                      )
-                    }
+                        activateTreePane(node.id, paneId)
+                      }
+
+                      // Claim the press so the STRIP's own pane-drag handler
+                      // (parent onPointerDown) can't also fire. startPaneDrag
+                      // does this internally; the session drag (shared with
+                      // sidebar rows) doesn't, so do it here for both paths.
+                      if (e.button === 0) {
+                        e.preventDefault()
+                        e.stopPropagation()
+                      }
+
+                      // A pane may own its tab drag (a session tab speaks the
+                      // session drop language — link/stack/split); `false` defers
+                      // to the generic pane move (the workspace tab on a fresh
+                      // draft has no session to link).
+                      if (!chrome.tabDrag?.(e, onTap, hideHeaderDoubleTap)) {
+                        startPaneDrag(
+                          paneId,
+                          e,
+                          onTap,
+                          stripRef.current ? { groupId: node.id, strip: stripRef.current } : undefined,
+                          hideHeaderDoubleTap,
+                          title
+                        )
+                      }
+                    }}
                     role="tab"
                     style={{ cursor: 'grab' }}
                   >
@@ -472,7 +503,7 @@ export function TreeGroup({
             // barely-tinted wash; the light blur reads as "edit mode" the same
             // way the zone editor's backdrop does.
             className="absolute inset-x-0 bottom-0 z-50 flex cursor-grab items-center justify-center outline-1 -outline-offset-2 outline-dashed backdrop-blur-[2px]"
-            onPointerDown={e => startPaneDrag(activeId, e)}
+            onPointerDown={e => startPaneDrag(activeId, e, undefined, undefined, undefined, active?.title ?? activeId)}
             style={{
               top: headerVisible ? 28 : 0,
               background:
@@ -490,7 +521,7 @@ export function TreeGroup({
 
       {/* FancyZones drop overlay — its own component so the per-frame drop
           hint re-renders only this (tiny) node, not the whole zone. */}
-      <ZoneDropOverlay isEmpty={isEmpty} node={node} />
+      <ZoneDropOverlay node={node} />
     </div>
   )
 }
@@ -565,26 +596,16 @@ const REGION: Record<DropPosition, CSSProperties> = {
   top: { bottom: '50%', left: REGION_PAD, right: REGION_PAD, top: REGION_PAD }
 }
 
-const EDGE_ARROW: Record<Exclude<DropPosition, 'center'>, string> = {
-  bottom: 'arrow-down',
-  left: 'arrow-left',
-  right: 'arrow-right',
-  top: 'arrow-up'
-}
-
 /**
  * The FancyZones drop overlay for one zone. Split out of TreeGroup so the
  * per-pointermove `$dropHint` churn re-renders only this lightweight node —
  * the zone's header, body, and menu-direction walk stay put during a drag.
  *
- * ONE dashed sheet per zone, in the attachment dropzone's design language
- * (DROP_SHEET_CLASS + DropPill — the composer drop and the zone targets speak
- * identically): a quiet outline over every eligible zone, accent-lit over the
- * target, morphing to the hovered half for an edge split. The pill names the
- * outcome; edges get their arrow.
+ * ONE dashed sheet per zone (DROP_SHEET_CLASS — the composer drop and the zone
+ * targets speak identically): a quiet outline over every eligible zone,
+ * accent-lit over the target, morphing to the hovered half for an edge split.
  */
-function ZoneDropOverlay({ isEmpty, node }: { isEmpty: boolean; node: GroupNode }) {
-  const { t } = useI18n()
+function ZoneDropOverlay({ node }: { node: GroupNode }) {
   const dragging = useStore($treeDragging)
   const hint = useStore($dropHint)
 
@@ -618,22 +639,11 @@ function ZoneDropOverlay({ isEmpty, node }: { isEmpty: boolean; node: GroupNode
   // Sub-positions only exist for a single-zone target (a Shift-span merges).
   const pos = primary && !multi ? (hint?.pos ?? 'center') : 'center'
   // Session drag over a CHAT zone's CENTER: the "link to chat" overlay inside
-  // the surface (ChatDropOverlay — the same sheet + pill) owns that region;
-  // this sheet fades out so the two never stack. A non-chat zone's center has
-  // no chat to link, so it shows the normal stack sheet. Edges act like a tab.
+  // the surface (ChatDropOverlay — the same sheet) owns that region; this sheet
+  // fades out so the two never stack. A non-chat zone's center has no chat to
+  // link, so it shows the normal stack sheet. Edges act like a tab.
   const centerLink = sessionDrag && primary && pos === 'center' && chatZone
 
-  const pill =
-    !primary || centerLink
-      ? null
-      : multi
-        ? { icon: 'combine', label: t.zones.spanHere }
-        : pos !== 'center'
-          ? { icon: EDGE_ARROW[pos], label: sessionDrag ? t.zones.openHere : t.zones.splitHere }
-          : isDragSource
-            ? { icon: 'discard', label: t.zones.staysHere }
-            : { icon: 'layers', label: isEmpty ? t.zones.moveHere : t.zones.stackHere }
-
   return (
     <div
       className="pointer-events-none absolute inset-0 z-40"
@@ -646,7 +656,7 @@ function ZoneDropOverlay({ isEmpty, node }: { isEmpty: boolean; node: GroupNode
           // backdrop-filter, and a blur interpolating while the insets glide
           // re-blurs half a zone every frame — the single most expensive
           // paint in the whole drag.
-          'absolute flex items-center justify-center transition-[top,right,bottom,left,background-color,border-color,opacity] duration-150 ease-out',
+          'absolute transition-[top,right,bottom,left,background-color,border-color,opacity] duration-150 ease-out',
           // Blur only the live target — idle outlines must not fog the app.
           active && !centerLink && DROP_SHEET_BLUR_CLASS,
           centerLink && 'opacity-0'
@@ -660,9 +670,7 @@ function ZoneDropOverlay({ isEmpty, node }: { isEmpty: boolean; node: GroupNode
             : 'color-mix(in srgb, var(--ui-accent) 5%, color-mix(in srgb, var(--dt-card) 25%, transparent))',
           borderColor: `color-mix(in srgb, var(--ui-accent) ${active ? 75 : 28}%, transparent)`
         }}
-      >
-        {pill && <DropPill icon={pill.icon}>{pill.label}</DropPill>}
-      </div>
+      />
     </div>
   )
 }

apps/desktop/src/components/pane-shell/tree/store.ts

@@ -13,6 +13,7 @@ import { translateNow } from '@/i18n'
 import { readJson, readKey, writeJson, writeKey } from '@/lib/storage'
 import { notify } from '@/store/notifications'
 import { clearAllPaneSizeOverrides } from '@/store/panes'
+import { isSecondaryWindow } from '@/store/windows'
 
 import {
   allPaneIds,
@@ -55,11 +56,19 @@ function loadPersisted(): LayoutNode | null {
 }
 
 function persist(tree: LayoutNode | null) {
+  // A secondary window (single-chat pop-out) shares the origin's localStorage;
+  // writing its stripped-down DEFAULT tree back would wipe the primary's layout.
+  if (isSecondaryWindow()) {
+    return
+  }
+
   writeJson(STORAGE_KEY, tree)
 }
 
-/** The live tree (null until a default is declared). */
-export const $layoutTree = atom<LayoutNode | null>(loadPersisted())
+/** The live tree (null until a default is declared). A secondary window ignores
+ *  the persisted (primary) layout and boots to the default — nothing but its
+ *  own routed session. */
+export const $layoutTree = atom<LayoutNode | null>(isSecondaryWindow() ? null : loadPersisted())
 
 /**
  * Which layout preset the current tree came from; `'custom'` after the user
@@ -234,7 +243,9 @@ export function trackActiveTreeGroup(): () => void {
 }
 
 const isUncloseablePane = (paneId: string): boolean =>
-  Boolean((registry.getArea('panes').find(c => c.id === paneId)?.data as { uncloseable?: boolean } | undefined)?.uncloseable)
+  Boolean(
+    (registry.getArea('panes').find(c => c.id === paneId)?.data as { uncloseable?: boolean } | undefined)?.uncloseable
+  )
 
 /** ⌘W "main tabs always": close the MAIN (workspace) zone's active tab, unless
  *  it's the uncloseable workspace itself. Returns false when there's nothing to
@@ -643,7 +654,8 @@ function adoptMissingPanes(target: LayoutNode, source: LayoutNode): LayoutNode {
     const targetId = (sibling ? findGroupOfPane(next, sibling)?.id : undefined) ?? groupLeafIds(next)[0]
 
     if (targetId) {
-      next = insertAtGroup(next, targetId, paneId, 'center') ?? next
+      // Silent adoption: don't steal the target zone's active tab (logs).
+      next = insertAtGroup(next, targetId, paneId, 'center', null, false) ?? next
       have.add(paneId)
     }
   }
@@ -742,7 +754,8 @@ function adoptContributedPanes(): void {
     const target = findGroupOfPane(next, anchor ?? '')?.id
 
     if (target) {
-      next = insertAtGroup(next, target, pane.id, dock?.pos ?? 'center', dock?.before) ?? next
+      // Silent adoption: don't front over the zone's active tab — a reveal does.
+      next = insertAtGroup(next, target, pane.id, dock?.pos ?? 'center', dock?.before, false) ?? next
 
       // An adopted pane ARRIVES with its chip showing — a surprise zone with
       // zero chrome has no obvious handle to drag or close. (Explicit reveal;
@@ -981,7 +994,34 @@ function paneGroup(paneId: string) {
 export function setPaneCollapsed(paneId: string, collapsed: boolean) {
   const group = paneGroup(paneId)
 
-  if (group && Boolean(group.minimized) !== collapsed) {
+  if (!group) {
+    return
+  }
+
+  // SHARED zone (terminal + logs, or a tool panel stacked with the workspace):
+  // one minimized flag but per-pane toggle stores — so "collapsed" is the
+  // ZONE's. Open → reveal + front; close acts ONLY for the on-screen tab. An
+  // inactive toggle folding its visible sibling is what re-collapsed the zone
+  // on every boot (broke collapse persistence).
+  if (group.panes.length > 1) {
+    if (collapsed && group.active === paneId) {
+      if (group.panes.some(isUncloseablePane)) {
+        // Workspace can't minimize (strands the app) → tab-switch to a sibling
+        // (guaranteed to exist by length > 1).
+        const at = group.panes.indexOf(paneId)
+
+        activateTreePane(group.id, group.panes[at - 1] ?? group.panes[at + 1])
+      } else {
+        toggleTreeGroupMinimized(group.id, true) // pure tool zone folds as a unit
+      }
+    } else if (!collapsed) {
+      revealTreePane(paneId)
+    }
+
+    return
+  }
+
+  if (Boolean(group.minimized) !== collapsed) {
     toggleTreeGroupMinimized(group.id, collapsed)
 
     if (!collapsed) {

apps/desktop/src/components/ui/drop-affordance.tsx

@@ -1,29 +1,11 @@
 /**
- * Shared drag-and-drop visual language — ONE dashed sheet + ONE floating pill,
- * used by every drop affordance (the composer file/session overlay, the layout
- * zone targets) so "you can drop here" reads identically everywhere.
+ * Shared drag-and-drop visual language — ONE dashed accent sheet, used by every
+ * drop affordance (the composer file/session overlay, the layout zone targets)
+ * so "you can drop here" reads identically everywhere.
  */
 
-import { Codicon } from '@/components/ui/codicon'
-import { cn } from '@/lib/utils'
-
 /** The sheet: a dashed region marking where a drop would land. */
 export const DROP_SHEET_CLASS = 'rounded-2xl border-2 border-dashed'
 
 /** Soft blur for the LIVE sheet only — idle outlines must not fog the app. */
 export const DROP_SHEET_BLUR_CLASS = 'backdrop-blur-[2px] [-webkit-backdrop-filter:blur(2px)]'
-
-/** The pill: icon + label floating over a sheet, naming the outcome. */
-export function DropPill({ children, className, icon }: React.ComponentProps<'div'> & { icon: string }) {
-  return (
-    <div
-      className={cn(
-        'flex items-center gap-2 rounded-full border border-[color-mix(in_srgb,var(--dt-composer-ring)_45%,transparent)] bg-[color-mix(in_srgb,var(--dt-card)_92%,transparent)] px-4 py-2 text-[0.8125rem] font-medium text-foreground shadow-composer',
-        className
-      )}
-    >
-      <Codicon className="shrink-0 text-(--ui-accent)" name={icon} size="1rem" />
-      {children}
-    </div>
-  )
-}

apps/desktop/src/components/ui/pane-tab.test.tsx

@@ -0,0 +1,92 @@
+import { cleanup, fireEvent, render, screen } from '@testing-library/react'
+import { afterEach, describe, expect, it, vi } from 'vitest'
+
+import { PaneTab, PaneTabLabel } from './pane-tab'
+
+afterEach(cleanup)
+
+describe('PaneTab close gestures', () => {
+  it('middle-click (button 1) closes', () => {
+    const onClose = vi.fn()
+    render(
+      <PaneTab onClose={onClose}>
+        <PaneTabLabel>tab</PaneTabLabel>
+      </PaneTab>
+    )
+
+    fireEvent(screen.getByText('tab'), new MouseEvent('auxclick', { bubbles: true, button: 1 }))
+    expect(onClose).toHaveBeenCalledTimes(1)
+  })
+
+  it('⌘-click (metaKey + button 0) closes — the Mac middle-click equivalent', () => {
+    const onClose = vi.fn()
+    render(
+      <PaneTab onClose={onClose}>
+        <PaneTabLabel>tab</PaneTabLabel>
+      </PaneTab>
+    )
+
+    fireEvent.pointerDown(screen.getByText('tab'), { button: 0, metaKey: true })
+    expect(onClose).toHaveBeenCalledTimes(1)
+  })
+
+  it('⌘-click preempts the shell drag/activate pointerdown handler', () => {
+    const onClose = vi.fn()
+    const onPointerDown = vi.fn()
+    render(
+      <PaneTab onClose={onClose} onPointerDown={onPointerDown}>
+        <PaneTabLabel>tab</PaneTabLabel>
+      </PaneTab>
+    )
+
+    fireEvent.pointerDown(screen.getByText('tab'), { button: 0, metaKey: true })
+    expect(onClose).toHaveBeenCalledTimes(1)
+    expect(onPointerDown).not.toHaveBeenCalled()
+  })
+
+  it('⌘-click swallows the follow-up activation click (capture phase)', () => {
+    const onClose = vi.fn()
+    const onActivate = vi.fn()
+    render(
+      <PaneTab onClose={onClose}>
+        <PaneTabLabel as="button" onClick={onActivate}>
+          tab
+        </PaneTabLabel>
+      </PaneTab>
+    )
+
+    fireEvent.click(screen.getByText('tab'), { button: 0, metaKey: true })
+    expect(onActivate).not.toHaveBeenCalled()
+  })
+
+  it('plain left-click neither closes nor blocks activation', () => {
+    const onClose = vi.fn()
+    const onActivate = vi.fn()
+    const onPointerDown = vi.fn()
+    render(
+      <PaneTab onClose={onClose} onPointerDown={onPointerDown}>
+        <PaneTabLabel as="button" onClick={onActivate}>
+          tab
+        </PaneTabLabel>
+      </PaneTab>
+    )
+
+    fireEvent.pointerDown(screen.getByText('tab'), { button: 0 })
+    fireEvent.click(screen.getByText('tab'), { button: 0 })
+    expect(onClose).not.toHaveBeenCalled()
+    expect(onPointerDown).toHaveBeenCalledTimes(1)
+    expect(onActivate).toHaveBeenCalledTimes(1)
+  })
+
+  it('does nothing without an onClose (uncloseable workspace tab)', () => {
+    const onPointerDown = vi.fn()
+    render(
+      <PaneTab onPointerDown={onPointerDown}>
+        <PaneTabLabel>tab</PaneTabLabel>
+      </PaneTab>
+    )
+
+    fireEvent.pointerDown(screen.getByText('tab'), { button: 0, metaKey: true })
+    expect(onPointerDown).toHaveBeenCalledTimes(1)
+  })
+})

apps/desktop/src/components/ui/pane-tab.tsx

@@ -12,14 +12,12 @@ export const PANE_TAB_STRIP_LINE_RIGHT = 'shadow-[inset_-1px_0_0_var(--ui-stroke
 const TAB =
   'group/tab relative flex shrink-0 items-center border-transparent bg-(--tab-bg) text-[0.6875rem] font-medium [-webkit-app-region:no-drag]'
 
-const TAB_HORIZONTAL =
-  'h-full min-w-0 max-w-48 border-b not-first:border-l not-first:border-l-(--ui-stroke-quaternary)'
+const TAB_HORIZONTAL = 'h-full min-w-0 max-w-48 border-b not-first:border-l not-first:border-l-(--ui-stroke-quaternary)'
 
 const TAB_VERTICAL =
   'w-full max-h-48 justify-center not-first:border-t not-first:border-t-(--ui-stroke-quaternary) [writing-mode:vertical-rl]'
 
-const TAB_ACTIVE =
-  'text-foreground [--tab-bg:var(--pane-tab-active-bg,var(--ui-editor-surface-background))]'
+const TAB_ACTIVE = 'text-foreground [--tab-bg:var(--pane-tab-active-bg,var(--ui-editor-surface-background))]'
 
 // Inactive = gutter. Hover = 4% translucent wash (VS Code/GitHub alpha hover),
 // not an opaque recolor — and never touch borders.
@@ -29,7 +27,8 @@ const TAB_IDLE =
 interface PaneTabProps extends React.ComponentProps<'div'> {
   active?: boolean
   dirty?: boolean
-  /** Middle-click close (no hover X — too easy to hit on small tabs). */
+  /** Close gesture, no hover X (too easy to hit on small tabs): middle-click,
+   *  or ⌘-click as the trackpad-friendly Mac equivalent. */
   onClose?: () => void
   /** Vertical rail form (collapsed sidebar zones). */
   vertical?: boolean
@@ -37,6 +36,12 @@ interface PaneTabProps extends React.ComponentProps<'div'> {
   side?: 'left' | 'right'
 }
 
+/** ⌘-click (metaKey + primary button) — the Mac has no middle button, so this
+ *  is the trackpad equivalent of middle-click-to-close. Guarded on metaKey so
+ *  it never collides with left-click (activate/drag) or ⌃-click (macOS context
+ *  menu). */
+const isMetaClose = (event: { button: number; metaKey: boolean }) => event.button === 0 && event.metaKey
+
 /**
  * Editor tab shell — preview rail + zone headers + collapsed vertical rails.
  *
@@ -51,6 +56,8 @@ export const PaneTab = React.forwardRef<HTMLDivElement, PaneTabProps>(function P
     onClose,
     onAuxClick,
     onMouseDown,
+    onPointerDown,
+    onClickCapture,
     vertical = false,
     side = 'left',
     children,
@@ -84,6 +91,17 @@ export const PaneTab = React.forwardRef<HTMLDivElement, PaneTabProps>(function P
 
         onAuxClick?.(event)
       }}
+      onClickCapture={event => {
+        // Sites whose tab activates on the label's own onClick (the preview
+        // rail) fire it AFTER our pointerdown close — swallow that stray click
+        // in the capture phase so it can't re-select the just-closed tab.
+        if (onClose && isMetaClose(event)) {
+          event.preventDefault()
+          event.stopPropagation()
+        }
+
+        onClickCapture?.(event)
+      }}
       onMouseDown={event => {
         if (onClose && event.button === 1) {
           event.preventDefault()
@@ -91,6 +109,20 @@ export const PaneTab = React.forwardRef<HTMLDivElement, PaneTabProps>(function P
 
         onMouseDown?.(event)
       }}
+      onPointerDown={event => {
+        // ⌘-click closes. Preempt here — the tab strips activate/drag on
+        // pointerdown (drag-session onTap), so we must claim the press before
+        // the shell's own handler starts a drag, and skip it entirely.
+        if (onClose && isMetaClose(event)) {
+          event.preventDefault()
+          event.stopPropagation()
+          onClose()
+
+          return
+        }
+
+        onPointerDown?.(event)
+      }}
       ref={ref}
       {...props}
     >

apps/desktop/src/i18n/en.ts

@@ -561,8 +561,7 @@ export const en: Translations = {
       localDesc: 'Start a private Hermes backend on localhost. This is the default and works offline.',
       remoteTitle: 'Remote gateway',
       remoteDesc: 'Connect this desktop shell to a remote Hermes backend.',
-      remoteAuthHint:
-        'Hosted gateways use OAuth or a username and password; self-hosted ones may use a session token.',
+      remoteAuthHint: 'Hosted gateways use OAuth or a username and password; self-hosted ones may use a session token.',
       cloudTitle: 'Hermes Cloud',
       cloudDesc: 'Sign in once to Hermes Cloud and pick from the agents on your account — no URL to paste.',
       cloudSignInTitle: 'Hermes Cloud',
@@ -1662,6 +1661,7 @@ export const en: Translations = {
       renameTitle: 'Rename session',
       renameDesc: 'Give this chat a memorable title. Leave empty to clear.',
       untitledPlaceholder: 'Untitled session',
+      untitledChat: id => `Chat ${id}`,
       ageNow: 'now',
       ageDay: 'd',
       ageHour: 'h',
@@ -2311,7 +2311,8 @@ export const en: Translations = {
     minimize: 'Minimize',
     restore: 'Restore',
     closeRunningTitle: 'Close running tab?',
-    closeRunningBody: 'This chat is still working (or waiting on your input). Closing the tab hides it — the session keeps its progress and can be reopened from the sidebar.',
+    closeRunningBody:
+      'This chat is still working (or waiting on your input). Closing the tab hides it — the session keeps its progress and can be reopened from the sidebar.',
     closeRunningConfirm: 'Close tab',
     closeOthers: 'Close others',
     closeToRight: 'Close to the right',
@@ -2322,12 +2323,6 @@ export const en: Translations = {
     dirDown: 'down',
     dirLeft: 'left',
     dirRight: 'right',
-    stackHere: 'Stack here',
-    moveHere: 'Move here',
-    splitHere: 'Split here',
-    openHere: 'Open here',
-    spanHere: 'Span here',
-    staysHere: 'Stays here',
     pluginDisabled: pluginId => `Plugin "${pluginId}" disabled`,
     pluginDisabledBody: 'Re-enable it in Settings → Plugins to bring the pane back.',
     missingPane: paneId => `missing pane: ${paneId}`,

apps/desktop/src/i18n/ja.ts

@@ -97,7 +97,8 @@ export const ja = defineLocale({
       remoteSignInHint: signInLabel =>
         `保存済みのリモートブラウザセッションからサインアウトし、${signInLabel}を開きます。代わりにバンドルされたバックエンドに切り替えるには「ローカルゲートウェイを使用」を選択してください。`,
       signOutAndSignIn: 'サインアウトして再サインイン',
-      remoteFailureHint: '「ゲートウェイ設定」でゲートウェイの URL とサインインを確認するか、ローカルゲートウェイに切り替えてください。',
+      remoteFailureHint:
+        '「ゲートウェイ設定」でゲートウェイの URL とサインインを確認するか、ローカルゲートウェイに切り替えてください。',
       hideRecentLogs: '最近のログを非表示',
       showRecentLogs: '最近のログを表示',
       signedInTitle: 'サインインしました',
@@ -1578,6 +1579,7 @@ export const ja = defineLocale({
       renameTitle: 'セッションの名前を変更',
       renameDesc: 'このチャットにわかりやすいタイトルをつけてください。空欄にするとクリアされます。',
       untitledPlaceholder: '無題のセッション',
+      untitledChat: id => `セッション ${id}`,
       ageNow: 'たった今',
       ageDay: '日',
       ageHour: '時間',
@@ -2238,12 +2240,6 @@ export const ja = defineLocale({
     dirDown: '下',
     dirLeft: '左',
     dirRight: '右',
-    stackHere: 'ここに重ねる',
-    moveHere: 'ここに移動',
-    splitHere: 'ここに分割',
-    openHere: 'ここに開く',
-    spanHere: 'ここにまたがる',
-    staysHere: 'ここにとどまる',
     pluginDisabled: pluginId => `プラグイン「${pluginId}」を無効化しました`,
     pluginDisabledBody: '設定 → プラグイン で再有効化するとペインが戻ります。',
     missingPane: paneId => `ペインが見つかりません: ${paneId}`,

apps/desktop/src/i18n/types.ts

@@ -1384,6 +1384,7 @@ export interface Translations {
       renameTitle: string
       renameDesc: string
       untitledPlaceholder: string
+      untitledChat: (id: string) => string
       ageNow: string
       ageDay: string
       ageHour: string
@@ -1947,12 +1948,6 @@ export interface Translations {
     dirDown: string
     dirLeft: string
     dirRight: string
-    stackHere: string
-    moveHere: string
-    splitHere: string
-    openHere: string
-    spanHere: string
-    staysHere: string
     pluginDisabled: (pluginId: string) => string
     pluginDisabledBody: string
     missingPane: (paneId: string) => string

apps/desktop/src/i18n/zh-hant.ts

@@ -1529,6 +1529,7 @@ export const zhHant = defineLocale({
       renameTitle: '重新命名工作階段',
       renameDesc: '為此聊天取一個好記的標題。留空則清除。',
       untitledPlaceholder: '未命名工作階段',
+      untitledChat: id => `工作階段 ${id}`,
       ageNow: '剛才',
       ageDay: '天',
       ageHour: '時',
@@ -2171,12 +2172,6 @@ export const zhHant = defineLocale({
     dirDown: '下',
     dirLeft: '左',
     dirRight: '右',
-    stackHere: '堆疊到此處',
-    moveHere: '移動到此處',
-    splitHere: '在此分割',
-    openHere: '在此開啟',
-    spanHere: '跨越到此處',
-    staysHere: '留在此處',
     pluginDisabled: pluginId => `外掛「${pluginId}」已停用`,
     pluginDisabledBody: '在 設定 → 外掛 中重新啟用即可恢復面板。',
     missingPane: paneId => `缺少面板：${paneId}`,

apps/desktop/src/i18n/zh.ts

@@ -316,7 +316,8 @@ export const zh: Translations = {
     },
     plugins: {
       title: '桌面插件',
-      blurb: '加载到此应用中的界面扩展——随构建捆绑，或放入 desktop-plugins 文件夹（包括 Hermes 编写的插件）。禁用会即时卸载插件并在重启后保持。',
+      blurb:
+        '加载到此应用中的界面扩展——随构建捆绑，或放入 desktop-plugins 文件夹（包括 Hermes 编写的插件）。禁用会即时卸载插件并在重启后保持。',
       count: n => `已安装 ${n} 个`,
       openFolder: '打开插件文件夹',
       rescan: '重新扫描',
@@ -1836,6 +1837,7 @@ export const zh: Translations = {
       renameTitle: '重命名会话',
       renameDesc: '给这个对话起一个好记的标题。留空则清除。',
       untitledPlaceholder: '无标题会话',
+      untitledChat: id => `会话 ${id}`,
       ageNow: '刚刚',
       ageDay: '天',
       ageHour: '时',
@@ -2483,12 +2485,6 @@ export const zh: Translations = {
     dirDown: '下',
     dirLeft: '左',
     dirRight: '右',
-    stackHere: '堆叠到此处',
-    moveHere: '移动到此处',
-    splitHere: '在此拆分',
-    openHere: '在此打开',
-    spanHere: '跨越到此处',
-    staysHere: '留在此处',
     pluginDisabled: pluginId => `插件“${pluginId}”已禁用`,
     pluginDisabledBody: '在 设置 → 插件 中重新启用即可恢复面板。',
     missingPane: paneId => `缺少面板：${paneId}`,

apps/desktop/src/lib/drag-ghost.ts

@@ -0,0 +1,43 @@
+/**
+ * A flat, pointer-following drag chip — the shared "what am I holding"
+ * affordance for in-app pointer drags. Plain DOM (no React) so it survives a
+ * pointer-capture drag without re-renders and tears down synchronously on Esc.
+ *
+ * Flat by design: a solid app surface with the dragged item's label, no
+ * border / radius / shadow, dimmed — it copies the real row/tab it represents
+ * rather than reading as a separate pill. Any pointer drag whose source does
+ * not stay visibly "held" can reuse this (the drag primitive in
+ * `pane-shell/tree/renderer/drag-session.ts`, and anything built on it).
+ */
+
+/** How far (px) the chip trails the pointer so it never sits under the cursor. */
+const OFFSET_X = 14
+const OFFSET_Y = 12
+
+export interface DragGhost {
+  /** Reposition the chip near the current pointer point. */
+  moveTo(x: number, y: number): void
+  /** Remove the chip from the DOM. Idempotent. */
+  destroy(): void
+}
+
+export function createDragGhost(label: string): DragGhost {
+  const el = document.createElement('div')
+
+  el.textContent = label
+  el.style.cssText =
+    'position:fixed;left:0;top:0;z-index:9999;pointer-events:none;max-width:16rem;overflow:hidden;' +
+    'text-overflow:ellipsis;white-space:nowrap;padding:0.25rem 0.625rem;opacity:0.6;' +
+    'background:var(--ui-sidebar-surface-background,var(--dt-card));color:var(--ui-text-primary);' +
+    'font-size:0.75rem;font-weight:500;will-change:transform'
+  document.body.appendChild(el)
+
+  return {
+    moveTo(x, y) {
+      el.style.transform = `translate3d(${x + OFFSET_X}px, ${y + OFFSET_Y}px, 0)`
+    },
+    destroy() {
+      el.remove()
+    }
+  }
+}

apps/desktop/src/store/session-states.ts

@@ -19,12 +19,19 @@
 import { atom, computed } from 'nanostores'
 
 import type { ClientSessionState } from '@/app/types'
-import { findGroup } from '@/components/pane-shell/tree/model'
-import { $activeTreeGroup, $layoutTree, noteActiveTreeGroup } from '@/components/pane-shell/tree/store'
+import { findGroup, findGroupOfPane } from '@/components/pane-shell/tree/model'
+import {
+  $activeTreeGroup,
+  $layoutTree,
+  moveTreePane,
+  noteActiveTreeGroup,
+  revealTreePane
+} from '@/components/pane-shell/tree/store'
 import { readJson, writeJson } from '@/lib/storage'
 
 import { $activeGatewayProfile, normalizeProfileKey } from './profile'
 import { $activeSessionId, $selectedStoredSessionId } from './session'
+import { isSecondaryWindow } from './windows'
 
 // ---------------------------------------------------------------------------
 // Reactive per-runtime session state (view mirror of the wiring cache).
@@ -48,7 +55,6 @@ export function dropSessionState(runtimeId: string) {
   $sessionStates.set(rest)
 }
 
-
 // ---------------------------------------------------------------------------
 // Session tiles.
 // ---------------------------------------------------------------------------
@@ -135,9 +141,17 @@ const profileKey = () => normalizeProfileKey($activeGatewayProfile.get())
 
 // Runtime ids are process-scoped — never trust a persisted one, so the live
 // atom hydrates from the stored (runtime-less) tiles for the active profile.
-export const $sessionTiles = atom<SessionTile[]>([...(tilesByProfile[profileKey()] ?? [])])
+// A secondary window (single-chat pop-out) shows ONLY its routed session — no
+// tiles, and no repopulation on a profile switch.
+export const $sessionTiles = atom<SessionTile[]>(isSecondaryWindow() ? [] : [...(tilesByProfile[profileKey()] ?? [])])
 
 function persistTiles() {
+  // Shares the origin's storage; a secondary window holds no tiles, so a write
+  // back would only wipe the primary's set.
+  if (isSecondaryWindow()) {
+    return
+  }
+
   writeJson(TILES_KEY, Object.keys(tilesByProfile).length === 0 ? null : tilesByProfile)
 }
 
@@ -156,10 +170,13 @@ function saveTiles(tiles: SessionTile[]) {
 
 // Profile switch: surface the new profile's tiles with runtime ids cleared so
 // they re-resume against the now-current gateway. (Fires immediately on
-// subscribe; harmless — the init value already matches.)
-$activeGatewayProfile.subscribe(() => {
-  $sessionTiles.set([...(tilesByProfile[profileKey()] ?? [])])
-})
+// subscribe; harmless — the init value already matches.) A secondary window
+// never carries tiles, so it stays out of this entirely.
+if (!isSecondaryWindow()) {
+  $activeGatewayProfile.subscribe(() => {
+    $sessionTiles.set([...(tilesByProfile[profileKey()] ?? [])])
+  })
+}
 
 export function patchSessionTile(storedSessionId: string, patch: Partial<SessionTile>) {
   saveTiles($sessionTiles.get().map(t => (t.storedSessionId === storedSessionId ? { ...t, ...patch } : t)))
@@ -213,12 +230,18 @@ export function sessionTileDelegate(): SessionTileDelegate | null {
   return delegate
 }
 
-/** Open (or front) a tile for a stored session, docked on `dir` (default
- *  right; `center` = stack into the anchor's zone, `before` = strip slot).
- *  Idempotent — an already-open tile keeps its original placement. The
- *  session LOADED IN MAIN never opens as a tile (same transcript twice,
- *  fighting over one runtime — silly). */
-export function openSessionTile(storedSessionId: string, dir: TileDock = 'right', anchor?: string, before?: null | string) {
+/** Open a tile for a stored session, or MOVE an existing one to the new dock
+ *  (`dir`; `center` = stack into the anchor's zone, `before` = strip slot). The
+ *  move path is what lets a tile's own TAB be dragged like a sidebar row — drop
+ *  it on a zone/edge/strip and the tile goes there (drop-on-a-composer links
+ *  instead, handled by the drag resolver). The session LOADED IN MAIN never
+ *  opens as a tile (same transcript twice, fighting one runtime — silly). */
+export function openSessionTile(
+  storedSessionId: string,
+  dir: TileDock = 'right',
+  anchor?: string,
+  before?: null | string
+) {
   const tiles = $sessionTiles.get()
 
   if (storedSessionId === $selectedStoredSessionId.get()) {
@@ -227,7 +250,49 @@ export function openSessionTile(storedSessionId: string, dir: TileDock = 'right'
 
   if (!tiles.some(t => t.storedSessionId === storedSessionId)) {
     saveTiles([...tiles, { anchor, before, dir, storedSessionId }])
+
+    return
   }
+
+  // Already open: relocate the existing pane to the drop target (pane-mirror
+  // only docks on first adoption, so a re-drag must move the tree pane itself).
+  const tree = $layoutTree.get()
+  const target = tree ? findGroupOfPane(tree, anchor ?? 'workspace')?.id : null
+
+  if (target) {
+    moveTreePane(`${TILE_PANE_PREFIX}${storedSessionId}`, { before: before ?? null, groupId: target, pos: dir })
+  }
+}
+
+/** If a session is already ON SCREEN — an open tile OR the one loaded in main —
+ *  front its tab (and focus its zone) and return true. A sidebar click on an
+ *  already-open chat JUMPS to its tab instead of reloading it; `false` means the
+ *  caller must load it into main. Covers the two dead clicks: an open tile, and
+ *  the main session while focus sits on a tile (route unchanged → no reload). */
+export function focusOpenSession(storedSessionId: string): boolean {
+  if ($sessionTiles.get().some(t => t.storedSessionId === storedSessionId)) {
+    const paneId = `${TILE_PANE_PREFIX}${storedSessionId}`
+    revealTreePane(paneId) // un-dismiss + adopt + front in its group
+    const tree = $layoutTree.get()
+    const group = tree ? findGroupOfPane(tree, paneId) : null
+
+    if (group) {
+      noteActiveTreeGroup(group.id)
+    }
+
+    return true
+  }
+
+  // Already the main session: front the workspace tab and drop tile focus so
+  // the readouts + sidebar highlight come home (a no-op when main is focused).
+  if (storedSessionId === $selectedStoredSessionId.get()) {
+    revealTreePane('workspace')
+    noteActiveTreeGroup(null)
+
+    return true
+  }
+
+  return false
 }
 
 // Closed-tab stack for ⌘⇧T reopen (in-memory) — keyed PER PROFILE like the
@@ -323,8 +388,13 @@ export const $focusedSessionState = computed([$focusedRuntimeId, $sessionStates]
 
 // A PRIMARY navigation (sidebar resume, route change, new chat) moves focus
 // home to the workspace — a previously-clicked tile must not keep owning the
-// titlebar/statusbar readouts for a session switch it had no part in.
-$selectedStoredSessionId.listen(() => noteActiveTreeGroup(null))
+// titlebar/statusbar readouts for a session switch it had no part in. It also
+// FRONTS the workspace tab: the resumed chat loads in the workspace pane, so a
+// zone parked on a tile tab must switch back or the click looks dead.
+$selectedStoredSessionId.listen(() => {
+  noteActiveTreeGroup(null)
+  revealTreePane('workspace')
+})
 
 // Dev hook for automation (mirrors __HERMES_LAYOUT_TREE__).
 if (import.meta.env.DEV && typeof window !== 'undefined') {