diff --git a/src/renderer/src/components/editor/DiffSectionItem.tsx b/src/renderer/src/components/editor/DiffSectionItem.tsx
index 2fc40c16cba..8847bad5fdc 100644
--- a/src/renderer/src/components/editor/DiffSectionItem.tsx
+++ b/src/renderer/src/components/editor/DiffSectionItem.tsx
@@ -87,16 +87,23 @@ export function DiffSectionItem({
 
   const fileDiff = useMemo(
     () =>
-      buildPierreFileDiff({
-        path: section.path,
-        oldPath: section.oldPath,
-        status: section.status,
-        originalContent: section.originalContent,
-        modifiedContent: section.modifiedContent,
-        // Why: keyed by content generation so the worker AST cache survives virtualization remounts.
-        cacheKey: `${section.key}:${section.contentGeneration ?? 0}`,
-        parseDiffOptions: buildPierreParseDiffOptions(settings?.diffShowWhitespace)
-      }),
+      section.collapsed ||
+      section.loading ||
+      section.loadOnDemand ||
+      section.error ||
+      section.diffResult?.kind === 'binary' ||
+      section.largeDiffRenderLimit?.limited
+        ? null
+        : buildPierreFileDiff({
+            path: section.path,
+            oldPath: section.oldPath,
+            status: section.status,
+            originalContent: section.originalContent,
+            modifiedContent: section.modifiedContent,
+            // Why: keyed by content generation so the worker AST cache survives virtualization remounts.
+            cacheKey: `${worktreeId}:${section.key}:${section.contentGeneration ?? 0}`,
+            parseDiffOptions: buildPierreParseDiffOptions(settings?.diffShowWhitespace)
+          }),
     [
       section.path,
       section.oldPath,
@@ -105,6 +112,13 @@ export function DiffSectionItem({
       section.modifiedContent,
       section.key,
       section.contentGeneration,
+      section.collapsed,
+      section.loading,
+      section.loadOnDemand,
+      section.error,
+      section.diffResult?.kind,
+      section.largeDiffRenderLimit?.limited,
+      worktreeId,
       settings?.diffShowWhitespace
     ]
   )
@@ -209,32 +223,33 @@ export function DiffSectionItem({
       return
     }
     return installEditorSaveShortcut(node, () => void handleSectionSaveRef.current(index))
-  }, [handleSectionSaveRef, index, isEditable])
+  }, [handleSectionSaveRef, index, isEditable, section.collapsed])
 
   const renderDiff = useCallback(
-    () => (
-      <PierreDiffSurface
-        fileDiff={fileDiff}
-        sideBySide={sideBySide}
-        settings={settings}
-        isEditable={isEditable}
-        collapseUnchanged
-        worktreeId={worktreeId ?? ''}
-        filePath={section.path}
-        language={detectLanguage(section.path)}
-        comments={comments}
-        onDeleteComment={handleDeleteComment}
-        onUpdateComment={handleUpdateComment}
-        onEditChange={handleEditChange}
-        onPostRender={handlePostRender}
-        onAddComment={hasLineCommentAction ? handleAddComment : undefined}
-        pendingComment={pendingComment}
-        addCommentPlaceholder={addLineCommentPlaceholder}
-        addCommentLabel={addLineCommentLabel}
-        onCancelComment={() => setPendingComment(null)}
-        onSubmitComment={handleSubmitComment}
-      />
-    ),
+    () =>
+      fileDiff ? (
+        <PierreDiffSurface
+          fileDiff={fileDiff}
+          sideBySide={sideBySide}
+          settings={settings}
+          isEditable={isEditable}
+          collapseUnchanged
+          worktreeId={worktreeId ?? ''}
+          filePath={section.path}
+          language={detectLanguage(section.path)}
+          comments={comments}
+          onDeleteComment={handleDeleteComment}
+          onUpdateComment={handleUpdateComment}
+          onEditChange={handleEditChange}
+          onPostRender={handlePostRender}
+          onAddComment={hasLineCommentAction ? handleAddComment : undefined}
+          pendingComment={pendingComment}
+          addCommentPlaceholder={addLineCommentPlaceholder}
+          addCommentLabel={addLineCommentLabel}
+          onCancelComment={() => setPendingComment(null)}
+          onSubmitComment={handleSubmitComment}
+        />
+      ) : null,
     [
       addLineCommentLabel,
       addLineCommentPlaceholder,
diff --git a/src/renderer/src/components/editor/DiffViewer.tsx b/src/renderer/src/components/editor/DiffViewer.tsx
index 0f062645bd9..fd46446764a 100644
--- a/src/renderer/src/components/editor/DiffViewer.tsx
+++ b/src/renderer/src/components/editor/DiffViewer.tsx
@@ -17,6 +17,7 @@ import { PierreDiffSurface } from './pierre-diff/PierreDiffSurface'
 import { buildPierreFileDiff } from './pierre-diff/pierre-diff-metadata'
 import { buildPierreParseDiffOptions } from './pierre-diff/pierre-diff-options'
 import { scrollPierreDiffToLine } from './pierre-diff/pierre-diff-scroll'
+import { getPierreDiffChangeTargets } from './pierre-diff/pierre-diff-change-targets'
 
 const EMPTY_DIFF_COMMENTS: readonly DecoratedDiffComment[] = []
 
@@ -70,19 +71,32 @@ export default function DiffViewer({
 
   const fileDiff = useMemo(
     () =>
-      buildPierreFileDiff({
-        path: relativePath,
-        status: 'modified',
-        originalContent,
-        modifiedContent,
-        cacheKey: modelKey,
-        parseDiffOptions: buildPierreParseDiffOptions(settings?.diffShowWhitespace)
-      }),
-    [relativePath, originalContent, modifiedContent, modelKey, settings?.diffShowWhitespace]
+      renderLimit.limited
+        ? null
+        : buildPierreFileDiff({
+            path: relativePath,
+            status: 'modified',
+            originalContent,
+            modifiedContent,
+            cacheKey: modelKey,
+            parseDiffOptions: buildPierreParseDiffOptions(settings?.diffShowWhitespace)
+          }),
+    [
+      relativePath,
+      originalContent,
+      modifiedContent,
+      modelKey,
+      settings?.diffShowWhitespace,
+      renderLimit.limited
+    ]
   )
 
   const { registerDiffNavigator, unregisterDiffNavigator } = useDiffNavigatorRegistration()
-  const changeLines = useMemo(() => fileDiff.hunks.map((hunk) => hunk.additionStart), [fileDiff])
+  const changeTargets = useMemo(() => getPierreDiffChangeTargets(fileDiff), [fileDiff])
+  const changeLines = useMemo(
+    () => changeTargets.map((target) => target.lineNumber),
+    [changeTargets]
+  )
 
   useEffect(() => {
     const container = scrollContainerRef.current
@@ -97,6 +111,7 @@ export default function DiffViewer({
           host: pierreHostRef.current,
           container,
           lineNumber,
+          side: changeTargets[hunkIndex]?.side,
           hunkIndex,
           hunkCount
         })
@@ -104,7 +119,13 @@ export default function DiffViewer({
     }
     registerDiffNavigator(navigator)
     return () => unregisterDiffNavigator(navigator)
-  }, [changeLines, registerDiffNavigator, renderLimit.limited, unregisterDiffNavigator])
+  }, [
+    changeLines,
+    changeTargets,
+    registerDiffNavigator,
+    renderLimit.limited,
+    unregisterDiffNavigator
+  ])
 
   const handlePostRender = useCallback((node: HTMLElement, phase: PostRenderPhase) => {
     pierreHostRef.current = phase === 'unmount' ? null : node
@@ -243,7 +264,7 @@ export default function DiffViewer({
               saveContentAvailable: largeDiffSaveContentAvailable
             })}
           />
-        ) : (
+        ) : fileDiff ? (
           <PierreDiffProviders>
             <PierreDiffSurface
               fileDiff={fileDiff}
@@ -267,7 +288,7 @@ export default function DiffViewer({
               onSubmitComment={handleSubmitComment}
             />
           </PierreDiffProviders>
-        )}
+        ) : null}
       </div>
     </div>
   )
diff --git a/src/renderer/src/components/editor/diff-section-live-render-limit.ts b/src/renderer/src/components/editor/diff-section-live-render-limit.ts
index 2a4ad6ba1e4..50ad082c731 100644
--- a/src/renderer/src/components/editor/diff-section-live-render-limit.ts
+++ b/src/renderer/src/components/editor/diff-section-live-render-limit.ts
@@ -1,6 +1,7 @@
 import type { DiffSection } from './diff-section-types'
 import {
   getLargeDiffRenderLimitFromCounts,
+  countLinesEmptyAsZero,
   type LargeDiffRenderLimit
 } from './large-diff-render-limit'
 
@@ -12,10 +13,12 @@ export function getLiveDiffSectionRenderLimit({
   modifiedContent: string
 }): LargeDiffRenderLimit {
   // Why: the renderer no longer owns a text model, so count lines from the draft itself.
-  const modifiedLineCount = modifiedContent.length === 0 ? 0 : modifiedContent.split('\n').length
+  const modifiedLineCount = countLinesEmptyAsZero(modifiedContent)
 
   return getLargeDiffRenderLimitFromCounts({
-    originalLineCount: section.largeDiffRenderLimit?.lineCounts?.original ?? 0,
+    originalLineCount:
+      section.largeDiffRenderLimit?.lineCounts?.original ??
+      countLinesEmptyAsZero(section.originalContent),
     modifiedLineCount,
     originalCharacterCount: section.originalContent.length,
     modifiedCharacterCount: modifiedContent.length
diff --git a/src/renderer/src/components/editor/pierre-diff/PierreDiffSurface.tsx b/src/renderer/src/components/editor/pierre-diff/PierreDiffSurface.tsx
index 1f3167452a9..303bc6ff584 100644
--- a/src/renderer/src/components/editor/pierre-diff/PierreDiffSurface.tsx
+++ b/src/renderer/src/components/editor/pierre-diff/PierreDiffSurface.tsx
@@ -1,7 +1,11 @@
 import { useCallback, useEffect, useMemo, useRef } from 'react'
 import { FileDiff } from '@pierre/diffs/react'
-import type { FileDiffMetadata, PostRenderPhase, SelectedLineRange } from '@pierre/diffs'
-import type { FileContents } from '@pierre/diffs'
+import type {
+  FileContents,
+  FileDiffMetadata,
+  PostRenderPhase,
+  SelectedLineRange
+} from '@pierre/diffs'
 import type { EditorOptions } from '@pierre/diffs/edit'
 import { useAppStore } from '@/store'
 import { RecoverableRenderErrorBoundary } from '@/components/error-boundaries/RecoverableRenderErrorBoundary'
@@ -103,11 +107,15 @@ export function PierreDiffSurface({
       }),
       enableGutterUtility: Boolean(onAddComment),
       onGutterUtilityClick: onAddComment
-        ? (range: SelectedLineRange) =>
+        ? (range: SelectedLineRange) => {
+            if (range.side === 'deletions' || range.endSide === 'deletions') {
+              return
+            }
             onAddComment({
               lineNumber: Math.max(range.start, range.end),
               startLine: range.start === range.end ? undefined : Math.min(range.start, range.end)
             })
+          }
         : undefined,
       onPostRender: onPostRender
         ? (node: HTMLElement, _instance: unknown, phase: PostRenderPhase) =>
@@ -121,8 +129,8 @@ export function PierreDiffSurface({
     [settings, editorFontZoomLevel]
   )
   const lineAnnotations = useMemo(
-    () => buildPierreDiffCommentAnnotations(comments, pendingComment),
-    [comments, pendingComment]
+    () => buildPierreDiffCommentAnnotations(comments, filePath, pendingComment),
+    [comments, filePath, pendingComment]
   )
   const editorOptions = useMemo<EditorOptions<'file-diff', PierreDiffAnnotationData, undefined>>(
     () => ({
diff --git a/src/renderer/src/components/editor/pierre-diff/pierre-diff-cache-identity.ts b/src/renderer/src/components/editor/pierre-diff/pierre-diff-cache-identity.ts
new file mode 100644
index 00000000000..69ad33158ec
--- /dev/null
+++ b/src/renderer/src/components/editor/pierre-diff/pierre-diff-cache-identity.ts
@@ -0,0 +1,36 @@
+type CachedIdentity = { original: string; modified: string; key: string }
+
+const identities = new Map<string, CachedIdentity>()
+const MAX_RETAINED_CHARACTERS = 4_000_000
+let retainedCharacters = 0
+let nextIdentity = 0
+
+// Pierre uses cache keys as content equality, including across mounted surfaces.
+export function getPierreDiffCacheIdentity(
+  scope: string,
+  original: string,
+  modified: string
+): string {
+  const previous = identities.get(scope)
+  if (previous?.original === original && previous.modified === modified) {
+    identities.delete(scope)
+    identities.set(scope, previous)
+    return previous.key
+  }
+  if (previous) {
+    retainedCharacters -= previous.original.length + previous.modified.length
+    identities.delete(scope)
+  }
+  const key = `orca-diff:${++nextIdentity}`
+  identities.set(scope, { original, modified, key })
+  retainedCharacters += original.length + modified.length
+  while (identities.size > 64 || retainedCharacters > MAX_RETAINED_CHARACTERS) {
+    const oldest = identities.entries().next().value
+    if (!oldest) {
+      break
+    }
+    retainedCharacters -= oldest[1].original.length + oldest[1].modified.length
+    identities.delete(oldest[0])
+  }
+  return key
+}
diff --git a/src/renderer/src/components/editor/pierre-diff/pierre-diff-change-targets.ts b/src/renderer/src/components/editor/pierre-diff/pierre-diff-change-targets.ts
new file mode 100644
index 00000000000..c63a16fe9d6
--- /dev/null
+++ b/src/renderer/src/components/editor/pierre-diff/pierre-diff-change-targets.ts
@@ -0,0 +1,28 @@
+import type { FileDiffMetadata } from '@pierre/diffs'
+
+export type PierreDiffChangeTarget = { lineNumber: number; side: 'additions' | 'deletions' }
+
+export function getPierreDiffChangeTargets(
+  diff: FileDiffMetadata | null
+): PierreDiffChangeTarget[] {
+  const targets: PierreDiffChangeTarget[] = []
+  for (const hunk of diff?.hunks ?? []) {
+    let additionLine = hunk.additionStart
+    let deletionLine = hunk.deletionStart
+    for (const block of hunk.hunkContent) {
+      if (block.type === 'context') {
+        additionLine += block.lines
+        deletionLine += block.lines
+      } else {
+        targets.push(
+          block.additions > 0
+            ? { lineNumber: Math.max(1, additionLine), side: 'additions' }
+            : { lineNumber: Math.max(1, deletionLine), side: 'deletions' }
+        )
+        additionLine += block.additions
+        deletionLine += block.deletions
+      }
+    }
+  }
+  return targets
+}
diff --git a/src/renderer/src/components/editor/pierre-diff/pierre-diff-comment-annotations.test.tsx b/src/renderer/src/components/editor/pierre-diff/pierre-diff-comment-annotations.test.tsx
new file mode 100644
index 00000000000..ba7302e8536
--- /dev/null
+++ b/src/renderer/src/components/editor/pierre-diff/pierre-diff-comment-annotations.test.tsx
@@ -0,0 +1,37 @@
+import { describe, expect, it, vi } from 'vitest'
+import type { DecoratedDiffComment } from '../../diff-comments/decorated-diff-comment'
+import { buildPierreDiffCommentAnnotations } from './pierre-diff-comment-annotations'
+
+vi.mock('../../diff-comments/DiffCommentCard', () => ({ DiffCommentCard: () => null }))
+vi.mock('../../diff-comments/DiffCommentPopover', () => ({ DiffCommentPopover: () => null }))
+vi.mock('../NotesSendMenu', () => ({ NotesSendMenu: () => null }))
+
+const note = (filePath: string): DecoratedDiffComment => ({
+  id: filePath,
+  filePath,
+  worktreeId: 'review',
+  lineNumber: 2,
+  body: 'review comment',
+  createdAt: 1,
+  side: 'modified'
+})
+
+describe('Pierre review annotations', () => {
+  it('keeps comments for other PR files out of this file', () => {
+    const annotations = buildPierreDiffCommentAnnotations(
+      [note('one.ts'), note('two.ts')],
+      'two.ts'
+    )
+    expect(annotations).toHaveLength(1)
+    expect(annotations[0].metadata).toMatchObject({
+      kind: 'comment',
+      comment: { filePath: 'two.ts' }
+    })
+  })
+
+  it('retains the range of an unsaved draft alongside existing notes', () => {
+    expect(
+      buildPierreDiffCommentAnnotations([note('one.ts')], 'one.ts', { lineNumber: 5, startLine: 3 })
+    ).toHaveLength(2)
+  })
+})
diff --git a/src/renderer/src/components/editor/pierre-diff/pierre-diff-comment-annotations.tsx b/src/renderer/src/components/editor/pierre-diff/pierre-diff-comment-annotations.tsx
index 7be031b6623..21807637cea 100644
--- a/src/renderer/src/components/editor/pierre-diff/pierre-diff-comment-annotations.tsx
+++ b/src/renderer/src/components/editor/pierre-diff/pierre-diff-comment-annotations.tsx
@@ -21,13 +21,16 @@ export type PierreDiffCommentAnnotation = DiffLineAnnotation<PierreDiffAnnotatio
  */
 export function buildPierreDiffCommentAnnotations(
   comments: readonly DecoratedDiffComment[],
+  filePath: string,
   draft?: { lineNumber: number; startLine?: number } | null
 ): PierreDiffCommentAnnotation[] {
-  const annotations: PierreDiffCommentAnnotation[] = comments.map((comment) => ({
-    side: 'additions',
-    lineNumber: comment.lineNumber,
-    metadata: { kind: 'comment', comment }
-  }))
+  const annotations: PierreDiffCommentAnnotation[] = comments
+    .filter((comment) => comment.filePath === filePath)
+    .map((comment) => ({
+      side: 'additions',
+      lineNumber: comment.lineNumber,
+      metadata: { kind: 'comment', comment }
+    }))
   if (draft) {
     annotations.push({
       side: 'additions',
diff --git a/src/renderer/src/components/editor/pierre-diff/pierre-diff-context-copy.ts b/src/renderer/src/components/editor/pierre-diff/pierre-diff-context-copy.ts
index 49c4c7d5642..f8fdd219700 100644
--- a/src/renderer/src/components/editor/pierre-diff/pierre-diff-context-copy.ts
+++ b/src/renderer/src/components/editor/pierre-diff/pierre-diff-context-copy.ts
@@ -2,6 +2,7 @@ import { formatCopiedSelectionWithContext } from '../selection-copy'
 import { editorShortcutMatches } from '../editor-shortcuts'
 import { formatShortcutLabel } from '@/hooks/useShortcutLabel'
 import { useAppStore } from '@/store'
+import { getPierreSelectionRange } from './pierre-diff-selection'
 import {
   PRIMARY_SELECTION_MAX_LENGTH,
   isPrimarySelectionEnabled,
@@ -10,15 +11,6 @@ import {
 
 const PRIMARY_SELECTION_DEBOUNCE_MS = 200
 
-/** Resolves the 1-based line of the row containing a selection boundary node. */
-function lineOf(node: Node | null): number | null {
-  const element = node instanceof Element ? node : (node?.parentElement ?? null)
-  const row = element?.closest('[data-line]')
-  const raw = row?.getAttribute('data-line')
-  const parsed = raw ? Number.parseInt(raw, 10) : Number.NaN
-  return Number.isFinite(parsed) ? parsed : null
-}
-
 /**
  * Restores `editor.copyContext` for Pierre-rendered diffs. Monaco exposed the
  * selection as an IRange; here the equivalent comes from the shadow root's
@@ -32,14 +24,19 @@ export function installPierreContextualCopy(
   // is an overlay pinned to the selection's client rect instead.
   const hint = document.createElement('div')
   hint.className =
-    'pointer-events-none fixed z-50 rounded-md border border-border/90 bg-background px-2.5 py-1 text-xs font-medium text-foreground shadow-[0_6px_18px_rgba(15,23,42,0.18)] backdrop-blur whitespace-nowrap'
+    'pointer-events-none fixed z-50 rounded-md border border-border/90 bg-background px-2.5 py-1 text-xs font-medium text-foreground shadow-floating backdrop-blur whitespace-nowrap'
   hint.style.display = 'none'
   document.body.appendChild(hint)
   let primarySelectionTimer: number | null = null
 
   const readSelection = (): Selection | null => {
     const root = container.querySelector('diffs-container')?.shadowRoot
-    return (root as unknown as { getSelection?: () => Selection | null })?.getSelection?.() ?? null
+    const selection =
+      (root as unknown as { getSelection?: () => Selection | null })?.getSelection?.() ?? null
+    return root?.contains(selection?.anchorNode ?? null) &&
+      root.contains(selection?.focusNode ?? null)
+      ? selection
+      : null
   }
 
   const hideHint = (): void => {
@@ -49,10 +46,9 @@ export function installPierreContextualCopy(
   const updateHint = (): void => {
     const selection = readSelection()
     const text = selection?.toString() ?? ''
-    const startLine = lineOf(selection?.anchorNode ?? null)
-    const endLine = lineOf(selection?.focusNode ?? null)
+    const range = getPierreSelectionRange(selection)
     // Why: copy-with-context is a multi-line affordance; a single line copies plainly.
-    if (!text || startLine == null || endLine == null || startLine === endLine) {
+    if (!text || !range || range.startLineNumber === range.endLineNumber) {
       hideHint()
       return
     }
@@ -95,19 +91,13 @@ export function installPierreContextualCopy(
     if (!editorShortcutMatches('editor.copyContext', event)) {
       return
     }
-    const host = container.querySelector('diffs-container')
-    const root = host?.shadowRoot
-    // Why: Chromium scopes the selection to the shadow root that owns the range.
-    const selection = (
-      root as unknown as { getSelection?: () => Selection | null }
-    )?.getSelection?.()
+    const selection = readSelection()
     const selectedText = selection?.toString() ?? ''
     if (!selectedText) {
       return
     }
-    const startLine = lineOf(selection?.anchorNode ?? null)
-    const endLine = lineOf(selection?.focusNode ?? null)
-    if (startLine == null || endLine == null) {
+    const range = getPierreSelectionRange(selection)
+    if (!range) {
       return
     }
     const { relativePath, language } = getFileInfo()
@@ -115,12 +105,7 @@ export function installPierreContextualCopy(
       relativePath,
       language,
       selectedText,
-      selection: {
-        startLineNumber: Math.min(startLine, endLine),
-        endLineNumber: Math.max(startLine, endLine),
-        startColumn: 1,
-        endColumn: 1
-      }
+      selection: range
     })
     if (!formatted) {
       return
@@ -133,9 +118,11 @@ export function installPierreContextualCopy(
 
   container.addEventListener('keydown', handleKeyDown, true)
   document.addEventListener('selectionchange', handleSelectionChange)
+  document.addEventListener('scroll', hideHint, true)
   return () => {
     container.removeEventListener('keydown', handleKeyDown, true)
     document.removeEventListener('selectionchange', handleSelectionChange)
+    document.removeEventListener('scroll', hideHint, true)
     if (primarySelectionTimer !== null) {
       window.clearTimeout(primarySelectionTimer)
     }
diff --git a/src/renderer/src/components/editor/pierre-diff/pierre-diff-metadata.test.ts b/src/renderer/src/components/editor/pierre-diff/pierre-diff-metadata.test.ts
new file mode 100644
index 00000000000..322eca3e236
--- /dev/null
+++ b/src/renderer/src/components/editor/pierre-diff/pierre-diff-metadata.test.ts
@@ -0,0 +1,61 @@
+import { describe, expect, it } from 'vitest'
+import { buildPierreFileDiff } from './pierre-diff-metadata'
+import { getPierreDiffChangeTargets } from './pierre-diff-change-targets'
+
+const input = {
+  path: 'example.ts',
+  status: 'modified',
+  cacheKey: 'workspace:file:0',
+  originalContent: 'one\ntwo\nthree\nfour\nfive\n',
+  modifiedContent: 'one\nTWO\nthree\nFOUR\nfive\n',
+  parseDiffOptions: { ignoreWhitespace: true }
+}
+
+describe('Pierre diff content identity and navigation', () => {
+  it('reuses unchanged content but invalidates edits, external updates, and whitespace options', () => {
+    const first = buildPierreFileDiff(input)
+    expect(buildPierreFileDiff(input).cacheKey).toBe(first.cacheKey)
+    for (const update of [
+      { modifiedContent: 'new draft\n' },
+      { originalContent: 'new base\n' },
+      { parseDiffOptions: { ignoreWhitespace: false } },
+      { path: 'another.ts' }
+    ]) {
+      expect(buildPierreFileDiff({ ...input, ...update }).cacheKey).not.toBe(first.cacheKey)
+    }
+  })
+
+  it('does not share stale content across workspaces with the same path and generation', () => {
+    const first = buildPierreFileDiff(input)
+    const second = buildPierreFileDiff({ ...input, modifiedContent: 'another workspace\n' })
+    expect(second.cacheKey).not.toBe(first.cacheKey)
+    expect(second.additionLines.join('')).toBe('another workspace\n')
+  })
+
+  it.each(['added', 'untracked', 'deleted'])('gives %s files worker cache identities', (status) => {
+    expect(buildPierreFileDiff({ ...input, status }).cacheKey).toBeTruthy()
+  })
+
+  it('navigates every change inside one context hunk', () => {
+    const diff = buildPierreFileDiff(input)
+    expect(diff.hunks).toHaveLength(1)
+    expect(getPierreDiffChangeTargets(diff)).toEqual([
+      { lineNumber: 2, side: 'additions' },
+      { lineNumber: 4, side: 'additions' }
+    ])
+  })
+
+  it('targets the old side for pure deletions, including deleted files', () => {
+    expect(
+      getPierreDiffChangeTargets(
+        buildPierreFileDiff({
+          ...input,
+          modifiedContent: 'one\nthree\nfour\nfive\n'
+        })
+      )
+    ).toEqual([{ lineNumber: 2, side: 'deletions' }])
+    expect(
+      getPierreDiffChangeTargets(buildPierreFileDiff({ ...input, status: 'deleted' }))
+    ).toEqual([{ lineNumber: 1, side: 'deletions' }])
+  })
+})
diff --git a/src/renderer/src/components/editor/pierre-diff/pierre-diff-metadata.ts b/src/renderer/src/components/editor/pierre-diff/pierre-diff-metadata.ts
index 669fd4b31af..11686186715 100644
--- a/src/renderer/src/components/editor/pierre-diff/pierre-diff-metadata.ts
+++ b/src/renderer/src/components/editor/pierre-diff/pierre-diff-metadata.ts
@@ -1,5 +1,6 @@
 import { parseDiffFromFile, type FileContents, type FileDiffMetadata } from '@pierre/diffs'
 import type { CreatePatchOptionsNonabortable } from 'diff'
+import { getPierreDiffCacheIdentity } from './pierre-diff-cache-identity'
 
 /** Statuses whose old side does not exist, so Pierre should render an add. */
 const ADDED_STATUSES = new Set(['added', 'untracked'])
@@ -36,12 +37,15 @@ export function buildPierreFileDiff({
 }): FileDiffMetadata {
   const isAdded = ADDED_STATUSES.has(status)
   const isDeleted = status === 'deleted'
+  const identity = getPierreDiffCacheIdentity(
+    JSON.stringify([cacheKey, path, oldPath, status, parseDiffOptions]),
+    originalContent,
+    modifiedContent
+  )
   const oldFile = isAdded
     ? null
-    : toFileContents(oldPath ?? path, originalContent, cacheKey && `${cacheKey}:old`)
-  const newFile = isDeleted
-    ? null
-    : toFileContents(path, modifiedContent, cacheKey && `${cacheKey}:new`)
+    : toFileContents(oldPath ?? path, originalContent, `${identity}:old`)
+  const newFile = isDeleted ? null : toFileContents(path, modifiedContent, `${identity}:new`)
 
-  return parseDiffFromFile(oldFile, newFile, parseDiffOptions)
+  return { ...parseDiffFromFile(oldFile, newFile, { ...parseDiffOptions }), cacheKey: identity }
 }
diff --git a/src/renderer/src/components/editor/pierre-diff/pierre-diff-render-gate.test.tsx b/src/renderer/src/components/editor/pierre-diff/pierre-diff-render-gate.test.tsx
new file mode 100644
index 00000000000..cd15401a0b3
--- /dev/null
+++ b/src/renderer/src/components/editor/pierre-diff/pierre-diff-render-gate.test.tsx
@@ -0,0 +1,65 @@
+// @vitest-environment happy-dom
+import { cleanup, render, screen } from '@testing-library/react'
+import { afterEach, expect, it, vi } from 'vitest'
+import DiffViewer from '../DiffViewer'
+import { buildPierreFileDiff } from './pierre-diff-metadata'
+import { getLargeDiffRenderLimit } from '../large-diff-render-limit'
+
+vi.mock('@/store', () => ({ useAppStore: (selector: (s: object) => unknown) => selector({}) }))
+vi.mock('../editor-shortcuts', () => ({ installEditorSaveShortcut: () => () => {} }))
+vi.mock('../diff-navigation-context', () => ({
+  useDiffNavigatorRegistration: () => ({
+    registerDiffNavigator: () => {},
+    unregisterDiffNavigator: () => {}
+  })
+}))
+vi.mock('./pierre-diff-metadata', () => ({
+  buildPierreFileDiff: vi.fn(() => {
+    throw new Error('limited content reached parser')
+  })
+}))
+vi.mock('./PierreDiffProviders', () => ({ PierreDiffProviders: () => null }))
+vi.mock('./PierreDiffSurface', () => ({ PierreDiffSurface: () => null }))
+vi.mock('../LargeDiffFallback', () => ({ LargeDiffFallback: () => <div>Large diff fallback</div> }))
+
+afterEach(() => {
+  cleanup()
+  vi.clearAllMocks()
+})
+
+it('renders a large-file fallback without synchronously computing the diff', () => {
+  const modifiedContent = 'x'.repeat(6_000_001)
+  render(
+    <DiffViewer
+      modelKey="large"
+      originalContent=""
+      modifiedContent={modifiedContent}
+      relativePath="large.txt"
+      filePath="large.txt"
+      language="plaintext"
+      sideBySide={false}
+    />
+  )
+  expect(screen.getByText('Large diff fallback')).toBeTruthy()
+  expect(buildPierreFileDiff).not.toHaveBeenCalled()
+})
+
+it('honors a host-provided render limit when the RPC bodies are omitted', () => {
+  render(
+    <DiffViewer
+      modelKey="remote"
+      originalContent=""
+      modifiedContent=""
+      relativePath="large.txt"
+      filePath="large.txt"
+      language="plaintext"
+      sideBySide={false}
+      largeDiffRenderLimit={getLargeDiffRenderLimit({
+        originalContent: '',
+        modifiedContent: 'x'.repeat(6_000_001)
+      })}
+    />
+  )
+  expect(screen.getByText('Large diff fallback')).toBeTruthy()
+  expect(buildPierreFileDiff).not.toHaveBeenCalled()
+})
diff --git a/src/renderer/src/components/editor/pierre-diff/pierre-diff-scroll.ts b/src/renderer/src/components/editor/pierre-diff/pierre-diff-scroll.ts
index 164187d0270..c536d5dc007 100644
--- a/src/renderer/src/components/editor/pierre-diff/pierre-diff-scroll.ts
+++ b/src/renderer/src/components/editor/pierre-diff/pierre-diff-scroll.ts
@@ -7,19 +7,28 @@ export function scrollPierreDiffToLine({
   host,
   container,
   lineNumber,
+  side = 'additions',
   hunkIndex,
   hunkCount
 }: {
   host: HTMLElement | null
   container: HTMLElement | null
   lineNumber: number
+  side?: 'additions' | 'deletions'
   hunkIndex: number
   hunkCount: number
 }): boolean {
   if (!container) {
     return false
   }
-  const row = host?.shadowRoot?.querySelector(`[data-line="${lineNumber}"]`)
+  const lineType = side === 'additions' ? 'change-addition' : 'change-deletion'
+  const root = host?.shadowRoot
+  const row =
+    root?.querySelector(`[data-code][data-${side}] [data-line="${lineNumber}"]`) ??
+    root?.querySelector(`[data-code] [data-line="${lineNumber}"][data-line-type="${lineType}"]`) ??
+    root?.querySelector(
+      `[data-code]:not([data-deletions]) [data-line="${lineNumber}"]:not([data-line-type="change-deletion"])`
+    )
   if (row instanceof HTMLElement) {
     const offset = row.getBoundingClientRect().top - container.getBoundingClientRect().top
     container.scrollTop += offset - container.clientHeight / 3
diff --git a/src/renderer/src/components/editor/pierre-diff/pierre-diff-selection.test.ts b/src/renderer/src/components/editor/pierre-diff/pierre-diff-selection.test.ts
new file mode 100644
index 00000000000..bbd34cf5f0d
--- /dev/null
+++ b/src/renderer/src/components/editor/pierre-diff/pierre-diff-selection.test.ts
@@ -0,0 +1,45 @@
+// @vitest-environment happy-dom
+import { describe, expect, it } from 'vitest'
+import { getPierreSelectionRange } from './pierre-diff-selection'
+import { formatCopiedSelectionWithContext } from '../selection-copy'
+
+function selection(endOffset: number): Selection {
+  const root = document.createElement('div')
+  root.innerHTML =
+    '<div data-line="10"><span>first</span> line</div><div data-line="11"><span>last</span> line</div>'
+  const range = document.createRange()
+  range.setStart(root.children[0].firstChild!.firstChild!, 1)
+  range.setEnd(root.children[1].firstChild!.firstChild!, endOffset)
+  return { rangeCount: 1, getRangeAt: () => range } as unknown as Selection
+}
+
+describe('Pierre contextual copy boundaries', () => {
+  it('includes a partially selected final line in the label', () => {
+    const range = getPierreSelectionRange(selection(2))!
+    expect(range).toEqual({ startLineNumber: 10, startColumn: 2, endLineNumber: 11, endColumn: 3 })
+    expect(
+      formatCopiedSelectionWithContext({
+        relativePath: 'file.ts',
+        language: 'typescript',
+        selectedText: 'irst line\nla',
+        selection: range
+      })
+    ).toContain('Lines: 10-11')
+  })
+
+  it('excludes a final line selected only at its first column', () => {
+    const range = getPierreSelectionRange(selection(0))!
+    expect(
+      formatCopiedSelectionWithContext({
+        relativePath: 'file.ts',
+        language: 'typescript',
+        selectedText: 'irst line\n',
+        selection: range
+      })
+    ).toContain('Line: 10\n')
+  })
+
+  it('ignores absent selections', () => {
+    expect(getPierreSelectionRange(null)).toBeNull()
+  })
+})
diff --git a/src/renderer/src/components/editor/pierre-diff/pierre-diff-selection.ts b/src/renderer/src/components/editor/pierre-diff/pierre-diff-selection.ts
new file mode 100644
index 00000000000..e197d6315d9
--- /dev/null
+++ b/src/renderer/src/components/editor/pierre-diff/pierre-diff-selection.ts
@@ -0,0 +1,33 @@
+import type { IRange } from 'monaco-editor'
+
+function selectionBoundary(node: Node, offset: number): { line: number; column: number } | null {
+  const element = node instanceof Element ? node : node.parentElement
+  const row = element?.closest('[data-line]')
+  const line = Number(row?.getAttribute('data-line'))
+  if (!row || !Number.isInteger(line) || line < 1) {
+    return null
+  }
+  const prefix = document.createRange()
+  prefix.selectNodeContents(row)
+  prefix.setEnd(node, offset)
+  return { line, column: prefix.toString().length + 1 }
+}
+
+// DOM ranges are ordered even when the user drags backwards.
+export function getPierreSelectionRange(selection: Selection | null): IRange | null {
+  if (!selection?.rangeCount) {
+    return null
+  }
+  const range = selection.getRangeAt(0)
+  const start = selectionBoundary(range.startContainer, range.startOffset)
+  const end = selectionBoundary(range.endContainer, range.endOffset)
+  if (!start || !end) {
+    return null
+  }
+  return {
+    startLineNumber: start.line,
+    startColumn: start.column,
+    endLineNumber: end.line,
+    endColumn: end.column
+  }
+}
diff --git a/src/renderer/src/components/editor/pierre-diff/use-pierre-diff-find.test.tsx b/src/renderer/src/components/editor/pierre-diff/use-pierre-diff-find.test.tsx
new file mode 100644
index 00000000000..3739c3e0cf7
--- /dev/null
+++ b/src/renderer/src/components/editor/pierre-diff/use-pierre-diff-find.test.tsx
@@ -0,0 +1,72 @@
+// @vitest-environment happy-dom
+import { act, renderHook, cleanup } from '@testing-library/react'
+import { afterEach, describe, expect, it, vi } from 'vitest'
+import { usePierreDiffFind } from './use-pierre-diff-find'
+
+vi.mock('../editor-shortcuts', () => ({
+  editorShortcutMatches: (_: string, event: KeyboardEvent) => event.key === 'f' && event.ctrlKey
+}))
+vi.mock('@/lib/shortcut-platform', () => ({ getShortcutPlatform: () => 'linux' }))
+
+afterEach(() => {
+  cleanup()
+  vi.useRealTimers()
+  document.body.replaceChildren()
+})
+
+function setup(isEditable: boolean) {
+  vi.useFakeTimers()
+  const container = document.createElement('div')
+  const host = document.createElement('diffs-container')
+  const shadow = host.attachShadow({ mode: 'open' })
+  container.append(host)
+  document.body.append(container)
+  const { result } = renderHook(() =>
+    usePierreDiffFind({ isEditable, containerRef: { current: container } })
+  )
+  const attachContent = () => {
+    const content = document.createElement('div')
+    content.setAttribute('contenteditable', 'true')
+    shadow.append(content)
+    return content
+  }
+  const find = () =>
+    act(() =>
+      result.current.handleContainerKeyDown({
+        key: 'f',
+        ctrlKey: true,
+        preventDefault: vi.fn(),
+        stopPropagation: vi.fn()
+      } as unknown as React.KeyboardEvent<HTMLElement>)
+    )
+  return { result, attachContent, find }
+}
+
+describe('Pierre find shortcut', () => {
+  it('opens on the first press when the editable surface is already attached', () => {
+    const { attachContent, find } = setup(true)
+    const content = attachContent()
+    const search = vi.fn()
+    content.addEventListener('keydown', search)
+    find()
+    act(() => vi.runOnlyPendingTimers())
+    expect(search).toHaveBeenCalledOnce()
+    expect(search.mock.calls[0][0]).toMatchObject({ key: 'f', ctrlKey: true })
+  })
+
+  it('opens after a read-only find session attaches and cancels on Escape', () => {
+    const { result, attachContent, find } = setup(false)
+    find()
+    expect(result.current.editEnabled).toBe(true)
+    const content = attachContent()
+    const search = vi.fn()
+    content.addEventListener('keydown', search)
+    act(() => result.current.handleEditorAttach({ focus: vi.fn() }))
+    act(() =>
+      result.current.handleContainerKeyDown({ key: 'Escape' } as React.KeyboardEvent<HTMLElement>)
+    )
+    act(() => vi.runOnlyPendingTimers())
+    expect(search).not.toHaveBeenCalled()
+    expect(result.current.editEnabled).toBe(false)
+  })
+})
diff --git a/src/renderer/src/components/editor/pierre-diff/use-pierre-diff-find.ts b/src/renderer/src/components/editor/pierre-diff/use-pierre-diff-find.ts
index efbc4d9b22b..443e4d13070 100644
--- a/src/renderer/src/components/editor/pierre-diff/use-pierre-diff-find.ts
+++ b/src/renderer/src/components/editor/pierre-diff/use-pierre-diff-find.ts
@@ -1,4 +1,4 @@
-import { useCallback, useRef, useState } from 'react'
+import { useCallback, useEffect, useRef, useState } from 'react'
 import type { EditorFocusOptions } from '@pierre/diffs/edit'
 import { getShortcutPlatform } from '@/lib/shortcut-platform'
 import { editorShortcutMatches } from '../editor-shortcuts'
@@ -10,7 +10,7 @@ import { editorShortcutMatches } from '../editor-shortcuts'
  */
 function findPierreContentElement(container: HTMLElement | null): HTMLElement | null {
   const host = container?.querySelector('diffs-container')
-  const editable = host?.shadowRoot?.querySelector('[contenteditable]')
+  const editable = host?.shadowRoot?.querySelector('[contenteditable="true"]')
   return editable instanceof HTMLElement ? editable : null
 }
 
@@ -61,9 +61,44 @@ export function usePierreDiffFind({
 }): PierreDiffFind {
   const [findActive, setFindActive] = useState(false)
   const pendingFindRef = useRef(false)
+  const replayingFindRef = useRef(false)
+  const findFrameRef = useRef<number | null>(null)
+
+  const openMountedSearch = useCallback(() => {
+    if (findFrameRef.current !== null) {
+      cancelAnimationFrame(findFrameRef.current)
+    }
+    findFrameRef.current = requestAnimationFrame(() => {
+      findFrameRef.current = null
+      const target = findPierreContentElement(containerRef.current)
+      if (!target || !pendingFindRef.current) {
+        return
+      }
+      pendingFindRef.current = false
+      target.focus({ preventScroll: true })
+      replayingFindRef.current = true
+      try {
+        dispatchPierreOpenSearchPanel(target)
+      } finally {
+        replayingFindRef.current = false
+      }
+    })
+  }, [containerRef])
+
+  useEffect(
+    () => () => {
+      if (findFrameRef.current !== null) {
+        cancelAnimationFrame(findFrameRef.current)
+      }
+    },
+    []
+  )
 
   const handleContainerKeyDown = useCallback(
     (event: React.KeyboardEvent<HTMLElement>) => {
+      if (replayingFindRef.current) {
+        return
+      }
       // Why: a find-only session must not outlive the search panel, or a
       // read-only diff stays editable forever after a single Cmd+F.
       if (findActive && event.key === 'Escape') {
@@ -71,15 +106,19 @@ export function usePierreDiffFind({
         setFindActive(false)
         return
       }
-      if (findActive || !editorShortcutMatches('editor.find', event)) {
+      if (!editorShortcutMatches('editor.find', event)) {
         return
       }
       event.preventDefault()
       event.stopPropagation()
       pendingFindRef.current = true
       setFindActive(true)
+      // Editable surfaces already attached; toggling find does not reattach them.
+      if (findPierreContentElement(containerRef.current)) {
+        openMountedSearch()
+      }
     },
-    [findActive]
+    [findActive, containerRef, openMountedSearch]
   )
 
   // Why: leaving the surface ends a find-only session too; the panel is gone.
@@ -99,20 +138,13 @@ export function usePierreDiffFind({
       if (!pendingFindRef.current) {
         return
       }
-      pendingFindRef.current = false
       editor.focus({ lineNumber: 'first-visible', preventScroll: true })
       // Why: the editable DOM is not focusable until after this commit paints,
       // so a same-tick dispatch misses Pierre's content element and the first
       // Cmd+F is swallowed — which is why it used to take two presses.
-      requestAnimationFrame(() => {
-        const target = findPierreContentElement(containerRef.current)
-        if (target) {
-          target.focus()
-          dispatchPierreOpenSearchPanel(target)
-        }
-      })
+      openMountedSearch()
     },
-    [containerRef]
+    [openMountedSearch]
   )
 
   const exitFind = useCallback(() => {