diff --git a/src/main/runtime/mobile-session-editor-projection.test.ts b/src/main/runtime/mobile-session-editor-projection.test.ts
index 1e8d9ff5a1d..b0a2803d984 100644
--- a/src/main/runtime/mobile-session-editor-projection.test.ts
+++ b/src/main/runtime/mobile-session-editor-projection.test.ts
@@ -54,6 +54,14 @@ function ownedSession(): WorkspaceSessionState {
   }
 }
 
+function activeOwnedSession(): WorkspaceSessionState {
+  return {
+    ...ownedSession(),
+    activeTabTypeByWorktree: { [WT]: 'editor' },
+    activeFileIdByWorktree: { [WT]: ownedEditorFileId(FILE, WT, undefined) }
+  }
+}
+
 describe('headless editor tabs under an owned id', () => {
   it('lists and retires the unified tab with the layout-owner switch on', () => {
     const session = ownedSession()
@@ -65,6 +73,21 @@ describe('headless editor tabs under an owned id', () => {
     expect(retired?.tabGroups?.[WT]?.[0]?.tabOrder).toEqual([])
   })
 
+  it('shows it as the active file', () => {
+    expect(buildHeadlessMobileSessionEditorTabs(WT, activeOwnedSession())).toEqual([
+      expect.objectContaining({ id: 'tab-1', isActive: true })
+    ])
+  })
+
+  it('clears the active file when it retires', () => {
+    const retired = retireHeadlessEditorTab(activeOwnedSession(), WT, {
+      id: 'tab-1',
+      filePath: FILE
+    })
+
+    expect(retired?.activeFileIdByWorktree?.[WT]).toBeNull()
+  })
+
   it('keeps matching by path alone with the switch off', () => {
     mocks.layoutOwnerIsMain = false
     expect(buildHeadlessMobileSessionEditorTabs(WT, ownedSession())).toEqual([
diff --git a/src/main/runtime/mobile-session-editor-projection.ts b/src/main/runtime/mobile-session-editor-projection.ts
index a307b3880c5..f44dae89398 100644
--- a/src/main/runtime/mobile-session-editor-projection.ts
+++ b/src/main/runtime/mobile-session-editor-projection.ts
@@ -33,6 +33,7 @@ function editorTab(
   file: PersistedOpenFile
 ): HeadlessEditorTab {
   const unifiedTab = editorUnifiedTab(session, worktreeId, file)
+  const activeFileId = session.activeFileIdByWorktree?.[worktreeId]
   const common = {
     // A file's id is its path, which is also the unified tab's entity.
     id: unifiedTab?.id ?? file.filePath,
@@ -42,7 +43,8 @@ function editorTab(
     isDirty: file.dirtyDraftContent !== undefined,
     isActive:
       session.activeTabTypeByWorktree?.[worktreeId] === 'editor' &&
-      session.activeFileIdByWorktree?.[worktreeId] === file.filePath,
+      !!activeFileId &&
+      editorTabShowsFile(activeFileId, file, worktreeId),
     color: unifiedTab?.color ?? null,
     isPinned: unifiedTab?.isPinned === true
   }
@@ -97,7 +99,8 @@ export function retireHeadlessEditorTab(
     tabOrder: withoutTab(group.tabOrder) ?? [],
     ...(group.recentTabIds ? { recentTabIds: withoutTab(group.recentTabIds) } : {})
   }))
-  const wasActiveFile = session.activeFileIdByWorktree?.[worktreeId] === tab.filePath
+  const activeFileId = session.activeFileIdByWorktree?.[worktreeId]
+  const wasActiveFile = !!activeFileId && editorTabShowsFile(activeFileId, file, worktreeId)
   return {
     ...session,
     openFilesByWorktree: {
diff --git a/src/renderer/src/runtime/layout-apply-hold-release.ts b/src/renderer/src/runtime/layout-apply-hold-release.ts
new file mode 100644
index 00000000000..111a7c1dd50
--- /dev/null
+++ b/src/renderer/src/runtime/layout-apply-hold-release.ts
@@ -0,0 +1,32 @@
+// The holds one layout.apply takes, released together and once: on its answer, or 15 s after the
+// send when the call or main's frame never comes (the holds would otherwise outlast main's frames).
+
+const HOLD_TIMEOUT_MS = 15_000
+
+export function releaseLayoutApplyHolds(
+  commandType: string,
+  holds: readonly ((() => void) | null)[]
+): () => void {
+  const held = holds.filter((hold) => hold !== null)
+  let released = false
+  // Why a task later: a handler that resolves a promise (drag-out) acts in its awaiting caller,
+  // microtasks after the handler returns.
+  const release = (): void => {
+    clearTimeout(expiry)
+    if (released) {
+      return
+    }
+    released = true
+    for (const hold of held) {
+      setTimeout(hold, 0)
+    }
+  }
+  const expiry =
+    held.length > 0
+      ? setTimeout(() => {
+          console.warn(`[layout-owner] ${commandType} hold released: no answer in 15s`)
+          release()
+        }, HOLD_TIMEOUT_MS)
+      : undefined
+  return release
+}
diff --git a/src/renderer/src/runtime/layout-apply-send.test.ts b/src/renderer/src/runtime/layout-apply-send.test.ts
index 24db2d01153..2c52386984d 100644
--- a/src/renderer/src/runtime/layout-apply-send.test.ts
+++ b/src/renderer/src/runtime/layout-apply-send.test.ts
@@ -2,9 +2,14 @@ import { beforeEach, describe, expect, it, vi } from 'vitest'
 import type { LayoutApplyReply } from '../../../shared/workspace-layout/workspace-layout-command-types'
 
 const mocks = vi.hoisted(() => {
-  const sent: { reply: LayoutApplyReply | Error } = { reply: { ok: true, result: {} } }
+  const sent: { reply: LayoutApplyReply | Error | Promise<LayoutApplyReply> } = {
+    reply: { ok: true, result: {} }
+  }
   const owner: { kind: 'resolved' | 'ambiguous' } = { kind: 'resolved' }
-  return { sent, owner }
+  // A frame that never comes keeps its waiter here.
+  const frame: { arrives: boolean; waiting: (() => void)[] } = { arrives: true, waiting: [] }
+  const paneRelease = vi.fn()
+  return { sent, owner, frame, paneRelease }
 })
 vi.mock('@/lib/resolve-owner', () => ({
   runtimeEnvironmentIdUnlessTwin: () => null,
@@ -20,9 +25,12 @@ vi.mock('@/runtime/runtime-rpc-client', () => ({
   })
 }))
 vi.mock('@/runtime/layout-frame-position', () => ({
-  afterLayoutFrame: (_seq: number | undefined, run: () => void) => run()
+  afterLayoutFrame: (_seq: number | undefined, run: () => void) =>
+    mocks.frame.arrives ? run() : mocks.frame.waiting.push(run)
+}))
+vi.mock('@/runtime/layout-owner-pane-intents', () => ({
+  holdTabPaneTree: () => mocks.paneRelease
 }))
-vi.mock('@/runtime/layout-owner-pane-intents', () => ({ holdTabPaneTree: () => () => {} }))
 
 import { recordLayoutApply, sendLayoutApply } from './layout-apply-send'
 import { isDrawnGroupLayoutHeld, isDrawnTabHeld } from './layout-owner-drawn-tab-holds'
@@ -144,3 +152,87 @@ describe('sendLayoutApply', () => {
     await vi.waitFor(() => expect(isDrawnGroupLayoutHeld('wt-1')).toBe(false))
   })
 })
+
+describe('sendLayoutApply holds with no answer', () => {
+  const RATIOS = { type: 'setGroupRatios', groupLayout: { type: 'leaf', groupId: 'g' } } as const
+  const NO_ANSWER = 'setGroupRatios hold released: no answer in 15s'
+
+  beforeEach(() => {
+    vi.useFakeTimers()
+    mocks.frame.arrives = true
+    mocks.frame.waiting = []
+    mocks.paneRelease.mockClear()
+    vi.spyOn(console, 'warn')
+      .mockClear()
+      .mockImplementation(() => {})
+    return () => vi.useRealTimers()
+  })
+
+  function sendHeld(workspace: string, command: Parameters<typeof sendLayoutApply>[2] = RATIOS) {
+    const handlers = { apply: vi.fn(), asToday: vi.fn(), refused: vi.fn(), drawn: true as const }
+    sendLayoutApply(NO_STATE, workspace, command, handlers)
+    return handlers
+  }
+
+  function ranNoHandler(handlers: ReturnType<typeof sendHeld>): void {
+    expect(handlers.apply).not.toHaveBeenCalled()
+    expect(handlers.asToday).not.toHaveBeenCalled()
+    expect(handlers.refused).not.toHaveBeenCalled()
+  }
+
+  it('frees the holds 15 s after a call that never answers, runs no handler and warns once', async () => {
+    mocks.sent.reply = new Promise<LayoutApplyReply>(() => {})
+    const handlers = sendHeld('wt-silent')
+
+    await vi.advanceTimersByTimeAsync(14_999)
+    expect(isDrawnGroupLayoutHeld('wt-silent')).toBe(true)
+    await vi.advanceTimersByTimeAsync(1)
+    await vi.advanceTimersByTimeAsync(1)
+
+    expect(isDrawnGroupLayoutHeld('wt-silent')).toBe(false)
+    ranNoHandler(handlers)
+    expect(console.warn).toHaveBeenCalledOnce()
+    expect(console.warn).toHaveBeenCalledWith(`[layout-owner] ${NO_ANSWER}`)
+  })
+
+  it("frees them when the answer came but main's frame never did", async () => {
+    mocks.sent.reply = { ok: true, result: {} }
+    mocks.frame.arrives = false
+    const handlers = sendHeld('wt-no-frame')
+
+    await vi.advanceTimersByTimeAsync(15_000)
+    await vi.advanceTimersByTimeAsync(1)
+
+    expect(isDrawnGroupLayoutHeld('wt-no-frame')).toBe(false)
+    ranNoHandler(handlers)
+    expect(console.warn).toHaveBeenCalledWith(`[layout-owner] ${NO_ANSWER}`)
+  })
+
+  it("frees a pane command's tree hold too, once, and a late frame still runs its handler", async () => {
+    mocks.sent.reply = { ok: true, result: { tabId: 'tab-1' } }
+    mocks.frame.arrives = false
+    const handlers = sendHeld('wt-pane', RENAME)
+
+    await vi.advanceTimersByTimeAsync(15_000)
+    await vi.advanceTimersByTimeAsync(1)
+    expect(mocks.paneRelease).toHaveBeenCalledOnce()
+
+    mocks.frame.waiting.forEach((run) => run())
+    await vi.advanceTimersByTimeAsync(1)
+    expect(handlers.apply).toHaveBeenCalledWith({ tabId: 'tab-1' })
+    expect(mocks.paneRelease).toHaveBeenCalledOnce()
+    expect(console.warn).toHaveBeenCalledOnce()
+  })
+
+  it('an answer in time stops the timer', async () => {
+    mocks.sent.reply = { ok: true, result: {} }
+    const handlers = sendHeld('wt-answered')
+
+    await vi.advanceTimersByTimeAsync(0)
+    expect(handlers.apply).toHaveBeenCalledOnce()
+    await vi.advanceTimersByTimeAsync(20_000)
+
+    expect(console.warn).not.toHaveBeenCalled()
+    expect(vi.getTimerCount()).toBe(0)
+  })
+})
diff --git a/src/renderer/src/runtime/layout-apply-send.ts b/src/renderer/src/runtime/layout-apply-send.ts
index 3f6bf6f7877..4b396eb7a34 100644
--- a/src/renderer/src/runtime/layout-apply-send.ts
+++ b/src/renderer/src/runtime/layout-apply-send.ts
@@ -7,6 +7,7 @@ import { callRuntimeRpc } from '@/runtime/runtime-rpc-client'
 import { afterLayoutFrame } from '@/runtime/layout-frame-position'
 import { holdTabPaneTree } from '@/runtime/layout-owner-pane-intents'
 import { holdDrawnTabs, type DrawnTabHold } from '@/runtime/layout-owner-drawn-tab-holds'
+import { releaseLayoutApplyHolds } from '@/runtime/layout-apply-hold-release'
 import type { SleepingAgentSessionRecord } from '../../../shared/agent-session-resume'
 import type { TabGroupLayoutNode } from '../../../shared/tab-types'
 import type { TerminalPaneLayoutNode } from '../../../shared/terminal-tab-types'
@@ -240,16 +241,7 @@ export function sendLayoutApply(
     PANE_COMMANDS.has(command.type) && 'tabId' in command ? holdTabPaneTree(command.tabId) : null
   const tabHolds = handlers.drawn ? drawnTabHolds(worktreeId, command) : []
   const tabHold = tabHolds.length > 0 ? holdDrawnTabs(tabHolds) : null
-  // Why a task later: a handler that resolves a promise (drag-out) acts in its awaiting caller,
-  // microtasks after the handler returns.
-  const release = (): void => {
-    if (hold) {
-      setTimeout(hold, 0)
-    }
-    if (tabHold) {
-      setTimeout(tabHold, 0)
-    }
-  }
+  const release = releaseLayoutApplyHolds(command.type, [hold, tabHold])
   void callRuntimeRpc<LayoutApplyReply>({ kind: 'local' }, 'layout.apply', {
     command: { ...command, workspace: worktreeId }
   })
diff --git a/src/shared/workspace-layout/old-client/old-client-session-tabs-projection-owned-editor.test.ts b/src/shared/workspace-layout/old-client/old-client-session-tabs-projection-owned-editor.test.ts
index 44e974b8bd1..194ca3f9a73 100644
--- a/src/shared/workspace-layout/old-client/old-client-session-tabs-projection-owned-editor.test.ts
+++ b/src/shared/workspace-layout/old-client/old-client-session-tabs-projection-owned-editor.test.ts
@@ -3,6 +3,7 @@
 
 import { beforeEach, describe, expect, it, vi } from 'vitest'
 import { ownedEditorFileId } from '../../workspace-session-pane-ownership'
+import { editorFileKey } from '../workspace-layout-editor-tab-file'
 import { projectSessionTabs, type SessionTabsFacts } from './old-client-session-tabs-projection'
 import { build, testContext, WS } from '../workspace-layout-command.test-fixture'
 
@@ -39,7 +40,13 @@ function projectOwnedReadme() {
   const view = {
     groups: {},
     panes: {},
-    editorDrafts: { [WS]: { [FILE]: { dirtyDraftContent: '# draft' } } }
+    editorDrafts: {
+      [WS]: {
+        [editorFileKey({ filePath: FILE, runtimeEnvironmentId: 'env-1' })]: {
+          dirtyDraftContent: '# draft'
+        }
+      }
+    }
   }
   return {
     tabId: results[0]!.tabId!,
diff --git a/src/shared/workspace-layout/old-client/old-client-session-tabs-projection.ts b/src/shared/workspace-layout/old-client/old-client-session-tabs-projection.ts
index 21cd02003a6..3724292589a 100644
--- a/src/shared/workspace-layout/old-client/old-client-session-tabs-projection.ts
+++ b/src/shared/workspace-layout/old-client/old-client-session-tabs-projection.ts
@@ -32,7 +32,7 @@ import {
   type DesktopLayoutView,
   type LayoutContentFacts
 } from '../workspace-layout-beside'
-import { editorTabFile } from '../workspace-layout-editor-tab-file'
+import { editorFileKey, editorTabFile } from '../workspace-layout-editor-tab-file'
 import type {
   LayoutContentTab,
   LayoutTab,
@@ -267,7 +267,8 @@ function editorRow(
     title: file.relativePath.split(/[\\/]/).pop() || file.relativePath || 'File',
     filePath: file.filePath,
     relativePath: file.relativePath,
-    isDirty: scope.view.editorDrafts[scope.key]?.[file.filePath]?.dirtyDraftContent !== undefined,
+    isDirty:
+      scope.view.editorDrafts[scope.key]?.[editorFileKey(file)]?.dirtyDraftContent !== undefined,
     color: tab.color ?? null,
     isPinned: tab.isPinned === true,
     isActive: scope.activeTabId === tab.id
diff --git a/src/shared/workspace-layout/workspace-layout-beside.ts b/src/shared/workspace-layout/workspace-layout-beside.ts
index 5330b7061cd..0fa036ddd2b 100644
--- a/src/shared/workspace-layout/workspace-layout-beside.ts
+++ b/src/shared/workspace-layout/workspace-layout-beside.ts
@@ -79,7 +79,7 @@ export type DesktopLayoutView = Pick<WorkspaceSessionState, ViewSessionField> &
   lastFocusedAt: Record<string, Record<string, number>>
   /** Terminal tab id → focused and expanded pane. */
   panes: Record<string, Pick<TerminalLayoutSnapshot, 'activeLeafId' | 'expandedLeafId'>>
-  /** Workspace key → file path → unsaved draft. */
+  /** Workspace key → file key (`editorFileKey`) → unsaved draft. */
   editorDrafts: Record<string, Record<string, EditorDraft>>
 }
 
diff --git a/src/shared/workspace-layout/workspace-layout-content-commands.ts b/src/shared/workspace-layout/workspace-layout-content-commands.ts
index bf13c7998dc..77a83d19d49 100644
--- a/src/shared/workspace-layout/workspace-layout-content-commands.ts
+++ b/src/shared/workspace-layout/workspace-layout-content-commands.ts
@@ -4,6 +4,7 @@ import type { EditorTabView } from '../editor-tab-view-types'
 import { ORCA_LAYOUT_OWNER_IS_MAIN } from '../layout-owner-switch'
 import { applied, refuse, workspaceOrEmpty, type Applied } from './workspace-layout-command-steps'
 import type { CommandOf, LayoutContext } from './workspace-layout-command-types'
+import { sameEditorFile } from './workspace-layout-editor-tab-file'
 import { admitsInitialSurface } from './workspace-layout-initial-surface'
 import type {
   LayoutContentTab,
@@ -88,7 +89,7 @@ export function openEditorTab(
   })
 }
 
-/** The file's record, replacing any held for its path. */
+/** The file's record, replacing any held for its path and owner. */
 function withEditorFile(
   model: WorkspaceLayoutModel,
   key: string,
@@ -98,7 +99,7 @@ function withEditorFile(
     return model
   }
   const workspace = model.workspaces[key]!
-  const files = (workspace.editorFiles ?? []).filter((entry) => entry.filePath !== file.filePath)
+  const files = (workspace.editorFiles ?? []).filter((entry) => !sameEditorFile(entry, file))
   return withWorkspace(model, key, { ...workspace, editorFiles: [...files, file] })
 }
 
diff --git a/src/shared/workspace-layout/workspace-layout-editor-file-owner.test.ts b/src/shared/workspace-layout/workspace-layout-editor-file-owner.test.ts
new file mode 100644
index 00000000000..85072bdc42d
--- /dev/null
+++ b/src/shared/workspace-layout/workspace-layout-editor-file-owner.test.ts
@@ -0,0 +1,198 @@
+// A local file and a runtime-environment file at one path in one workspace are two records: each
+// open, reload, move and close touches its own owner's record only.
+
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+import { FLOATING_TERMINAL_WORKTREE_ID } from '../constants'
+import { LOCAL_EXECUTION_HOST_ID } from '../execution-host'
+import { ownedEditorFileId } from '../workspace-session-pane-ownership'
+import type { PersistedOpenFile, WorkspaceSessionState } from '../workspace-session-state-types'
+import { applyLayoutCommand } from './workspace-layout-commands'
+import type { CommandOf } from './workspace-layout-command-types'
+import { build, testContext } from './workspace-layout-command.test-fixture'
+import { loadWorkspaceLayout } from './workspace-layout-load'
+import type { LayoutEditorFile, WorkspaceLayoutModel } from './workspace-layout-model'
+import { patchStoredSession } from './workspace-layout-record-patch'
+import { saveWorkspaceLayout } from './workspace-layout-save'
+import { addWorkspace, emptySession, GIT_KEY } from './workspace-layout-session.test-fixture'
+
+const mocks = vi.hoisted(() => ({ layoutOwnerIsMain: true }))
+vi.mock('../layout-owner-switch', () => ({
+  get ORCA_LAYOUT_OWNER_IS_MAIN() {
+    return mocks.layoutOwnerIsMain
+  }
+}))
+
+beforeEach(() => {
+  mocks.layoutOwnerIsMain = true
+})
+
+const FLOATING = FLOATING_TERMINAL_WORKTREE_ID
+const PATH = '/Users/dev/notes/todo.md'
+const ENV = 'env-1'
+const LOCAL_FILE: LayoutEditorFile = {
+  filePath: PATH,
+  relativePath: 'todo.md',
+  language: 'markdown'
+}
+const RUNTIME_FILE: LayoutEditorFile = { ...LOCAL_FILE, runtimeEnvironmentId: ENV }
+
+const localId = (key: string): string => ownedEditorFileId(PATH, key, null)
+const runtimeId = (key: string): string => ownedEditorFileId(PATH, key, ENV)
+
+const open = (key: string, fileId: string, file: LayoutEditorFile): CommandOf<'openEditorTab'> => ({
+  type: 'openEditorTab',
+  workspace: key,
+  tabId: fileId,
+  fileId,
+  contentType: 'editor',
+  file
+})
+
+/** Both owners' tabs open in `key`: the local one under `localTabId`, the runtime one owned. */
+function bothOpen(key: string, localTabId: string) {
+  const ctx = testContext()
+  const built = build(ctx, [
+    open(key, localTabId, LOCAL_FILE),
+    open(key, runtimeId(key), RUNTIME_FILE)
+  ])
+  return { ctx, model: built.model }
+}
+
+const owners = (model: WorkspaceLayoutModel, key: string) =>
+  (model.workspaces[key]?.editorFiles ?? []).map((file) => file.runtimeEnvironmentId ?? 'local')
+
+function closeTab(model: WorkspaceLayoutModel, key: string, tabId: string): WorkspaceLayoutModel {
+  const closed = applyLayoutCommand(
+    model,
+    { type: 'closeTabs', workspace: key, tabIds: [tabId] },
+    testContext()
+  )
+  if (!closed.ok) {
+    throw new Error(closed.code)
+  }
+  return closed.model
+}
+
+function persisted(key: string, file: LayoutEditorFile, draft: string): PersistedOpenFile {
+  return { ...file, worktreeId: key, dirtyDraftContent: draft }
+}
+
+describe('editor file records keyed by path and owner, layout-owner build', () => {
+  it("opening the second owner's file keeps the first owner's record", () => {
+    const { model } = bothOpen(FLOATING, localId(FLOATING))
+
+    expect(owners(model, FLOATING)).toEqual(['local', ENV])
+  })
+
+  it("reopening one owner's file replaces only that owner's record", () => {
+    const { ctx, model } = bothOpen(FLOATING, localId(FLOATING))
+    const renamed = { ...RUNTIME_FILE, relativePath: 'renamed.md' }
+
+    const again = build(ctx, [open(FLOATING, runtimeId(FLOATING), renamed)], model)
+
+    expect(again.model.workspaces[FLOATING]!.editorFiles).toEqual([LOCAL_FILE, renamed])
+  })
+
+  it('a reload keeps both records, each with its own unsaved draft', () => {
+    const stored: WorkspaceSessionState = addWorkspace(emptySession(), FLOATING, [
+      {
+        id: 'group-1',
+        tabs: [
+          { id: localId(FLOATING), kind: 'editor' },
+          { id: runtimeId(FLOATING), kind: 'editor' }
+        ]
+      }
+    ])
+    stored.openFilesByWorktree = {
+      [FLOATING]: [
+        persisted(FLOATING, LOCAL_FILE, 'local draft'),
+        persisted(FLOATING, RUNTIME_FILE, 'runtime draft')
+      ]
+    }
+    let id = 0
+    const loaded = loadWorkspaceLayout(LOCAL_EXECUTION_HOST_ID, stored, {
+      mintId: () => `minted-${++id}`,
+      mintLeafId: () => `00000000-0000-4000-8000-${String(++id).padStart(12, '0')}`
+    })
+
+    const saved = saveWorkspaceLayout(loaded)
+
+    expect(saved.openFilesByWorktree?.[FLOATING]).toEqual(stored.openFilesByWorktree[FLOATING])
+  })
+
+  it("moving one owner's tab moves only that owner's record", () => {
+    const ctx = testContext()
+    const { model } = build(ctx, [
+      open(GIT_KEY, PATH, LOCAL_FILE),
+      open(GIT_KEY, runtimeId(GIT_KEY), RUNTIME_FILE),
+      open(FLOATING, localId(FLOATING), LOCAL_FILE)
+    ])
+    const groupId = model.workspaces[FLOATING]!.groups[0]!.id
+
+    const moved = build(
+      ctx,
+      [
+        {
+          type: 'moveTabToWorkspace',
+          workspace: GIT_KEY,
+          toWorkspace: FLOATING,
+          tabs: [
+            {
+              tabId: runtimeId(GIT_KEY),
+              newTabId: runtimeId(FLOATING),
+              newEntityId: runtimeId(FLOATING)
+            }
+          ],
+          groupId,
+          file: RUNTIME_FILE
+        }
+      ],
+      model
+    )
+
+    expect(owners(moved.model, GIT_KEY)).toEqual(['local'])
+    expect(owners(moved.model, FLOATING)).toEqual(['local', ENV])
+  })
+
+  it.each([
+    ['floating, both owned', FLOATING, localId(FLOATING)],
+    ['a path-id local tab', GIT_KEY, PATH]
+  ])('closing the local tab keeps the runtime record (%s)', (_name, key, localTabId) => {
+    const { model } = bothOpen(key, localTabId)
+
+    expect(owners(closeTab(model, key, localTabId), key)).toEqual([ENV])
+  })
+
+  it.each([
+    ['floating, both owned', FLOATING, localId(FLOATING)],
+    ['a path-id local tab', GIT_KEY, PATH]
+  ])('closing the runtime tab keeps the local record (%s)', (_name, key, localTabId) => {
+    const { model } = bothOpen(key, localTabId)
+
+    expect(owners(closeTab(model, key, runtimeId(key)), key)).toEqual(['local'])
+  })
+
+  it("writing the second owner's open onto the stored session adds its record", () => {
+    const local = { ...LOCAL_FILE, worktreeId: FLOATING }
+    const runtime = { ...RUNTIME_FILE, worktreeId: FLOATING }
+    const session = (files: PersistedOpenFile[]): WorkspaceSessionState => ({
+      ...emptySession(),
+      openFilesByWorktree: { [FLOATING]: files }
+    })
+
+    const patched = patchStoredSession(
+      session([local]),
+      session([local]),
+      session([local, runtime])
+    )
+
+    expect(patched.openFilesByWorktree?.[FLOATING]).toEqual([local, runtime])
+  })
+
+  it('match by path alone when the switch is off, as a headless host does today', () => {
+    mocks.layoutOwnerIsMain = false
+    const { model } = bothOpen(FLOATING, localId(FLOATING))
+
+    expect(owners(model, FLOATING)).toEqual([ENV])
+  })
+})
diff --git a/src/shared/workspace-layout/workspace-layout-editor-tab-file.ts b/src/shared/workspace-layout/workspace-layout-editor-tab-file.ts
index 07b00f6e104..6c35805dca7 100644
--- a/src/shared/workspace-layout/workspace-layout-editor-tab-file.ts
+++ b/src/shared/workspace-layout/workspace-layout-editor-tab-file.ts
@@ -16,6 +16,32 @@ export function editorTabShowsFile(entityId: string, file: FileOwner, worktreeId
   )
 }
 
+/**
+ * A file record's key among its workspace's records: its path, and in a layout-owner build its
+ * runtime owner too, since a local and a runtime-environment file can share a path.
+ */
+export function editorFileKey(file: FileOwner): string {
+  // Why no worktree: every record keyed here belongs to one workspace, or moves between two.
+  return ORCA_LAYOUT_OWNER_IS_MAIN
+    ? ownedEditorFileId(file.filePath, '', file.runtimeEnvironmentId)
+    : file.filePath
+}
+
+export function sameEditorFile(a: FileOwner, b: FileOwner): boolean {
+  return editorFileKey(a) === editorFileKey(b)
+}
+
+/** Whether an editor file id (a bare path or an owned id) names one of the workspace's records. */
+export function holdsEditorFileId(
+  workspace: { worktreeId: string; editorFiles?: readonly FileOwner[] },
+  fileId: string
+): boolean {
+  return (
+    workspace.editorFiles?.some((file) => editorTabShowsFile(fileId, file, workspace.worktreeId)) ??
+    false
+  )
+}
+
 export function editorTabFile<F extends FileOwner>(
   workspace: { worktreeId: string; editorFiles?: readonly F[] },
   entityId: string
@@ -24,3 +50,39 @@ export function editorTabFile<F extends FileOwner>(
     editorTabShowsFile(entityId, file, workspace.worktreeId)
   )
 }
+
+type EditorWorkspace<F> = {
+  worktreeId: string
+  tabs: readonly { entityId: string }[]
+  editorFiles?: readonly F[]
+}
+
+/**
+ * The records an editor tab shows. The window gives a path's bare id to one owner only, so a bare
+ * id that matches several records names those no owned-id tab claims.
+ */
+function editorTabFiles<F extends FileOwner>(workspace: EditorWorkspace<F>, entityId: string): F[] {
+  const shown = (workspace.editorFiles ?? []).filter((file) =>
+    editorTabShowsFile(entityId, file, workspace.worktreeId)
+  )
+  if (shown.length < 2) {
+    return shown
+  }
+  const ids = new Set(workspace.tabs.map((tab) => tab.entityId))
+  const unclaimed = shown.filter(
+    (file) =>
+      !ids.has(ownedEditorFileId(file.filePath, workspace.worktreeId, file.runtimeEnvironmentId))
+  )
+  return unclaimed.length > 0 ? unclaimed : shown
+}
+
+/** Whether a record stays once `entityId`'s last tab closed: not that tab's, or another tab's too. */
+export function keptAfterEditorClose<F extends FileOwner>(
+  before: EditorWorkspace<F>,
+  after: { tabs: readonly { entityId: string }[] },
+  entityId: string
+): (file: F) => boolean {
+  const closed = new Set(editorTabFiles(before, entityId))
+  const shown = new Set(after.tabs.flatMap((tab) => editorTabFiles(before, tab.entityId)))
+  return (file) => !closed.has(file) || shown.has(file)
+}
diff --git a/src/shared/workspace-layout/workspace-layout-load-records.ts b/src/shared/workspace-layout/workspace-layout-load-records.ts
index 5e21e75f152..f8316b75c63 100644
--- a/src/shared/workspace-layout/workspace-layout-load-records.ts
+++ b/src/shared/workspace-layout/workspace-layout-load-records.ts
@@ -6,7 +6,7 @@ import {
   EDITOR_DRAFT_FIELDS
 } from './workspace-layout-beside'
 import { childRecord, omitStoredFields, pickStoredFields } from './stored-record-fields'
-import { editorTabShowsFile } from './workspace-layout-editor-tab-file'
+import { editorFileKey, editorTabShowsFile } from './workspace-layout-editor-tab-file'
 import type { WorkspaceLoadArgs } from './workspace-layout-load-types'
 import type { LayoutBrowserTab, LayoutEditorFile, LayoutTab } from './workspace-layout-model'
 
@@ -54,7 +54,7 @@ export function loadEditorFiles(
   return files.map((file) => {
     const draft = pickStoredFields(file, EDITOR_DRAFT_FIELDS)
     if (Object.keys(draft).length > 0) {
-      childRecord(view.editorDrafts, key)[file.filePath] = draft
+      childRecord(view.editorDrafts, key)[editorFileKey(file)] = draft
     }
     const fileTabs = tabs.filter(
       (tab) => tab.kind === 'editor' && editorTabShowsFile(tab.entityId, file, worktreeId)
diff --git a/src/shared/workspace-layout/workspace-layout-record-patch.ts b/src/shared/workspace-layout/workspace-layout-record-patch.ts
index f0a8fe823fa..f16cfc8d417 100644
--- a/src/shared/workspace-layout/workspace-layout-record-patch.ts
+++ b/src/shared/workspace-layout/workspace-layout-record-patch.ts
@@ -3,7 +3,9 @@
 // key order, carried leftovers); diffing the save before the command against the save after it
 // isolates the command, and only those records and fields are written.
 
+import { ORCA_LAYOUT_OWNER_IS_MAIN } from '../layout-owner-switch'
 import type { WorkspaceSessionState } from '../workspace-session-state-types'
+import { editorFileKey } from './workspace-layout-editor-tab-file'
 import { adoptTouchedFoldedRows } from './workspace-layout-folded-rows'
 
 type Json = Record<string, unknown>
@@ -13,7 +15,15 @@ const LIST_FIELDS: Record<string, (record: Json) => unknown> = {
   tabsByWorktree: (record) => record.id,
   unifiedTabs: (record) => record.id,
   tabGroups: (record) => record.id,
-  openFilesByWorktree: (record) => record.filePath,
+  // Why the switch: a local and a runtime-environment file can share a path in a layout-owner build.
+  openFilesByWorktree: (record) =>
+    ORCA_LAYOUT_OWNER_IS_MAIN && typeof record.filePath === 'string'
+      ? editorFileKey({
+          filePath: record.filePath,
+          runtimeEnvironmentId:
+            typeof record.runtimeEnvironmentId === 'string' ? record.runtimeEnvironmentId : null
+        })
+      : record.filePath,
   browserTabsByWorktree: (record) => record.id
 }
 
diff --git a/src/shared/workspace-layout/workspace-layout-save.ts b/src/shared/workspace-layout/workspace-layout-save.ts
index 384fdabffeb..86161cc02e7 100644
--- a/src/shared/workspace-layout/workspace-layout-save.ts
+++ b/src/shared/workspace-layout/workspace-layout-save.ts
@@ -15,7 +15,7 @@ import {
   FACT_SESSION_FIELDS,
   VIEW_SESSION_FIELDS
 } from './workspace-layout-beside'
-import { editorTabShowsFile } from './workspace-layout-editor-tab-file'
+import { editorFileKey, editorTabShowsFile } from './workspace-layout-editor-tab-file'
 import type { LoadedWorkspaceLayout } from './workspace-layout-load-types'
 import { collectLayoutLeafIdsInOrder } from './terminal-pane-tree'
 import { paneKeyOf, tabsInOrder, type WorkspaceLayout } from './workspace-layout-model'
@@ -107,7 +107,7 @@ function saveWorkspace(
       ...(previewTabs.some((tab) => editorTabShowsFile(tab.entityId, file, worktreeId))
         ? { isPreview: true }
         : {}),
-      ...view.editorDrafts[key]?.[file.filePath]
+      ...view.editorDrafts[key]?.[editorFileKey(file)]
     }))
   }
   if (workspace.browserTabs) {
diff --git a/src/shared/workspace-layout/workspace-layout-tab-commands.ts b/src/shared/workspace-layout/workspace-layout-tab-commands.ts
index 79845c83f28..ee2617fe706 100644
--- a/src/shared/workspace-layout/workspace-layout-tab-commands.ts
+++ b/src/shared/workspace-layout/workspace-layout-tab-commands.ts
@@ -1,8 +1,9 @@
+import { ORCA_LAYOUT_OWNER_IS_MAIN } from '../layout-owner-switch'
 import { filterRecord, omitStoredFields, withoutKey } from './stored-record-fields'
 import { canReplacePreviewContentType, partitionPinnedTabOrder } from './tab-order'
 import { getNextTerminalOrdinal } from './terminal-tab-ordinal'
 import { layoutContainsLeafId } from './terminal-pane-tree'
-import { editorTabShowsFile } from './workspace-layout-editor-tab-file'
+import { editorTabShowsFile, keptAfterEditorClose } from './workspace-layout-editor-tab-file'
 import {
   applied,
   boundPtyIds,
@@ -104,7 +105,10 @@ export function closeTab(
     next = {
       ...next,
       editorFiles: next.editorFiles.filter(
-        (file) => !editorTabShowsFile(tab.entityId, file, next.worktreeId)
+        // Why the switch: shipped builds close through this code too.
+        ORCA_LAYOUT_OWNER_IS_MAIN
+          ? keptAfterEditorClose(workspace, next, tab.entityId)
+          : (file) => !editorTabShowsFile(tab.entityId, file, next.worktreeId)
       )
     }
   }
diff --git a/src/shared/workspace-layout/workspace-layout-view-prune.ts b/src/shared/workspace-layout/workspace-layout-view-prune.ts
index 758f53cf727..a4f7af8143b 100644
--- a/src/shared/workspace-layout/workspace-layout-view-prune.ts
+++ b/src/shared/workspace-layout/workspace-layout-view-prune.ts
@@ -7,6 +7,7 @@ import {
 } from '../worktree/host-qualified-identity'
 import { filterRecord, withoutKey } from './stored-record-fields'
 import { collectLayoutLeafIdsInOrder } from './terminal-pane-tree'
+import { editorFileKey, holdsEditorFileId } from './workspace-layout-editor-tab-file'
 import type {
   LayoutTerminalTab,
   WorkspaceLayout,
@@ -24,7 +25,7 @@ function terminalTabs(workspace: WorkspaceLayout): LayoutTerminalTab[] {
 function clearMissingIds(
   byWorkspace: Record<string, string | null> | undefined,
   workspaces: Workspaces,
-  ids: (workspace: WorkspaceLayout) => readonly string[]
+  holds: (workspace: WorkspaceLayout, id: string) => boolean
 ): Record<string, string | null> | undefined {
   if (!byWorkspace) {
     return undefined
@@ -32,11 +33,16 @@ function clearMissingIds(
   return Object.fromEntries(
     Object.entries(byWorkspace).map(([key, id]) => {
       const workspace = workspaces[key]
-      return [key, id === null || !workspace || ids(workspace).includes(id) ? id : null]
+      return [key, id === null || !workspace || holds(workspace, id) ? id : null]
     })
   )
 }
 
+const holdsId =
+  (ids: (workspace: WorkspaceLayout) => readonly string[]) =>
+  (workspace: WorkspaceLayout, id: string): boolean =>
+    ids(workspace).includes(id)
+
 /** Keeps a held workspace's entries for ids it still has; other workspaces are untouched. */
 function keepHeldIds<T>(
   byWorkspace: Record<string, Record<string, T>>,
@@ -54,8 +60,8 @@ function keepHeldIds<T>(
 
 const tabIds = (workspace: WorkspaceLayout): string[] => workspace.tabs.map((tab) => tab.id)
 const groupIds = (workspace: WorkspaceLayout): string[] => workspace.groups.map((group) => group.id)
-const filePaths = (workspace: WorkspaceLayout): string[] =>
-  workspace.editorFiles?.map((file) => file.filePath) ?? []
+const fileKeys = (workspace: WorkspaceLayout): string[] =>
+  workspace.editorFiles?.map(editorFileKey) ?? []
 const browserTabIds = (workspace: WorkspaceLayout): string[] =>
   workspace.browserTabs?.map((tab) => tab.id) ?? []
 const terminalTabIds = (workspace: WorkspaceLayout): string[] =>
@@ -113,7 +119,7 @@ export function pruneViewRecord(
     groups,
     lastFocusedAt: keepHeldIds(record.lastFocusedAt, workspaces, tabIds),
     panes,
-    editorDrafts: keepHeldIds(record.editorDrafts, workspaces, filePaths)
+    editorDrafts: keepHeldIds(record.editorDrafts, workspaces, fileKeys)
   }
   if (activeGroups) {
     pruned.activeGroupIdByWorktree = filterRecord(
@@ -125,21 +131,21 @@ export function pruneViewRecord(
     pruned.activeTabIdByWorktree = clearMissingIds(
       record.activeTabIdByWorktree,
       workspaces,
-      terminalTabIds
+      holdsId(terminalTabIds)
     )
   }
   if (record.activeFileIdByWorktree) {
     pruned.activeFileIdByWorktree = clearMissingIds(
       record.activeFileIdByWorktree,
       workspaces,
-      filePaths
+      holdsEditorFileId
     )
   }
   if (record.activeBrowserTabIdByWorktree) {
     pruned.activeBrowserTabIdByWorktree = clearMissingIds(
       record.activeBrowserTabIdByWorktree,
       workspaces,
-      browserTabIds
+      holdsId(browserTabIds)
     )
   }
   return pruned
diff --git a/src/shared/workspace-layout/workspace-layout-views-owned-file.test.ts b/src/shared/workspace-layout/workspace-layout-views-owned-file.test.ts
new file mode 100644
index 00000000000..430b676219b
--- /dev/null
+++ b/src/shared/workspace-layout/workspace-layout-views-owned-file.test.ts
@@ -0,0 +1,71 @@
+// The active file under an owned id (a floating file, a second owner of a path) is a file the
+// workspace holds: reading or pruning the view keeps it, as for a bare path id.
+
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+import { ownedEditorFileId } from '../workspace-session-pane-ownership'
+import { emptyModel, WS } from './workspace-layout-command.test-fixture'
+import type { WorkspaceLayout } from './workspace-layout-model'
+import { pruneViewRecord } from './workspace-layout-view-prune'
+import {
+  emptyLayoutViewRecord,
+  resolveWorkspaceSelection,
+  type LayoutViewRecord
+} from './workspace-layout-views'
+
+const mocks = vi.hoisted(() => ({ layoutOwnerIsMain: true }))
+vi.mock('../layout-owner-switch', () => ({
+  get ORCA_LAYOUT_OWNER_IS_MAIN() {
+    return mocks.layoutOwnerIsMain
+  }
+}))
+
+beforeEach(() => {
+  mocks.layoutOwnerIsMain = true
+})
+
+const PATH = '/srv/app/README.md'
+const OWNED = ownedEditorFileId(PATH, WS, 'env-1')
+
+function workspace(): WorkspaceLayout {
+  return {
+    worktreeId: WS,
+    groups: [{ id: 'g1', tabOrder: ['t1'] }],
+    tabs: [
+      { id: 't1', entityId: OWNED, kind: 'editor', createdAt: 1, customTitle: null, color: null }
+    ],
+    editorFiles: [
+      {
+        filePath: PATH,
+        relativePath: 'README.md',
+        language: 'markdown',
+        runtimeEnvironmentId: 'env-1'
+      }
+    ]
+  }
+}
+
+const activeOn = (id: string): LayoutViewRecord => ({
+  ...emptyLayoutViewRecord(),
+  activeFileIdByWorktree: { [WS]: id }
+})
+
+describe('an owned-id active file, layout-owner build', () => {
+  it('reads back as the active file', () => {
+    expect(resolveWorkspaceSelection(activeOn(OWNED), WS, workspace()).activeFileId).toBe(OWNED)
+  })
+
+  it('stays through a prune', () => {
+    const pruned = pruneViewRecord(activeOn(OWNED), {
+      ...emptyModel(),
+      workspaces: { [WS]: workspace() }
+    })
+
+    expect(pruned.activeFileIdByWorktree?.[WS]).toBe(OWNED)
+  })
+
+  it('falls back when no record holds it', () => {
+    const gone = ownedEditorFileId(PATH, WS, 'env-2')
+
+    expect(resolveWorkspaceSelection(activeOn(gone), WS, workspace()).activeFileId).toBeNull()
+  })
+})
diff --git a/src/shared/workspace-layout/workspace-layout-views.ts b/src/shared/workspace-layout/workspace-layout-views.ts
index b6e90d3db05..8fd308b2281 100644
--- a/src/shared/workspace-layout/workspace-layout-views.ts
+++ b/src/shared/workspace-layout/workspace-layout-views.ts
@@ -4,6 +4,7 @@
 
 import { collectLayoutLeafIdsInOrder } from './terminal-pane-tree'
 import type { DesktopLayoutView } from './workspace-layout-beside'
+import { holdsEditorFileId } from './workspace-layout-editor-tab-file'
 import type { WorkspaceLayout } from './workspace-layout-model'
 
 /** The one workspace window of an app instance. */
@@ -131,9 +132,7 @@ export function resolveWorkspaceSelection(
         : (workspace.groups[0]?.id ?? null),
     groups,
     panes,
-    activeFileId: workspace.editorFiles?.some((file) => file.filePath === activeFileId)
-      ? (activeFileId ?? null)
-      : null,
+    activeFileId: activeFileId && holdsEditorFileId(workspace, activeFileId) ? activeFileId : null,
     activeBrowserTabId: workspace.browserTabs?.some((tab) => tab.id === activeBrowserTabId)
       ? (activeBrowserTabId ?? null)
       : null
diff --git a/src/shared/workspace-layout/workspace-layout-workspace-move.ts b/src/shared/workspace-layout/workspace-layout-workspace-move.ts
index 1258e9369fd..547b3fdcbbc 100644
--- a/src/shared/workspace-layout/workspace-layout-workspace-move.ts
+++ b/src/shared/workspace-layout/workspace-layout-workspace-move.ts
@@ -10,6 +10,7 @@ import {
   type Applied
 } from './workspace-layout-command-steps'
 import type { CommandOf, LayoutContext } from './workspace-layout-command-types'
+import { sameEditorFile } from './workspace-layout-editor-tab-file'
 import type { LayoutTab, WorkspaceLayout, WorkspaceLayoutModel } from './workspace-layout-model'
 import { removeTabFromWorkspace, withWorkspace } from './workspace-layout-removal'
 import { withoutKey } from './stored-record-fields'
@@ -105,7 +106,7 @@ function moveEditorFile(
   file: NonNullable<CommandOf<'moveTabToWorkspace'>['file']>
 ): { source: WorkspaceLayout; target: WorkspaceLayout } {
   const others = (files: WorkspaceLayout['editorFiles']) =>
-    files?.filter((entry) => entry.filePath !== file.filePath)
+    files?.filter((entry) => !sameEditorFile(entry, file))
   const sourceFiles = others(source.editorFiles)
   return {
     source: sourceFiles ? { ...source, editorFiles: sourceFiles } : source,