fix(ui): keep current summary visible next to stale compaction markers

The settled current-summary card was only created when no compaction
marker was loaded at all. A transcript with older (stale) markers plus a
newer `compression_anchor_summary` that no loaded marker references
therefore lost the current summary, which master still rendered.

Decide the fallback from `_latestCompressionReferenceMessage()`
(`referenceMessageRawIdx < 0`) instead of marker presence, and feed that
decision into `_selectCompactionCardPlacements()` before any card node is
built so the fallback is the single preserved-task owner and marker cards
never attach the task list a second time.

Add a render-level regression that executes the real `renderMessages()`
over 220 messages, three stale markers, one preserved task-list message
and a newer summary: the current summary is visible and exactly one task
owner is rendered, in full, virtualized and server-truncated windows.

static/ui.js

@@ -15373,7 +15373,11 @@ function _loadedCompactionMarkerRawIdxs(messages){
 // A settled compaction whose marker sits before the server-loaded tail must
 // remain visible at the top of that tail. Anchoring it to an old assistant/tool
 // turn can bury it inside a hidden worklog, which makes compaction look absent.
-function _selectCompactionCardPlacements(markerRawIdxs,firstRenderedRawIdx){
+// `currentSummaryFallback` is true when the session's current summary matches
+// no loaded marker and therefore renders as its own settled card. That card is
+// the newest compaction the user can see, so it owns the preserved task cards
+// and no marker card may attach them again.
+function _selectCompactionCardPlacements(markerRawIdxs,firstRenderedRawIdx,currentSummaryFallback=false){
   const preWindowMarkers=[];
   const inlineMarkers=[];
   const boundary=Number.isFinite(firstRenderedRawIdx)?firstRenderedRawIdx:-1;
@@ -15383,11 +15387,13 @@ function _selectCompactionCardPlacements(markerRawIdxs,firstRenderedRawIdx){
     if(rawIdx<boundary) preWindowMarkers.push(rawIdx);
     else inlineMarkers.push(rawIdx);
   }
-  const taskOwner=inlineMarkers.length
-    ?{kind:'inline',rawIdx:inlineMarkers[inlineMarkers.length-1]}
-    :!preWindowMarkers.length
-      ?null
-      :{kind:'pre-window',rawIdx:preWindowMarkers[preWindowMarkers.length-1]};
+  const taskOwner=currentSummaryFallback
+    ?{kind:'current-summary',rawIdx:-1}
+    :inlineMarkers.length
+      ?{kind:'inline',rawIdx:inlineMarkers[inlineMarkers.length-1]}
+      :!preWindowMarkers.length
+        ?null
+        :{kind:'pre-window',rawIdx:preWindowMarkers[preWindowMarkers.length-1]};
   return {preWindowMarkers,inlineMarkers,taskOwner};
 }
 function _insertCompactionCardNodes(entries,taskOwner,insertNode){
@@ -17072,7 +17078,17 @@ function renderMessages(options){
   // order; markers inside the window stay inline.
   const firstRenderedRawIdx=renderVisWithIdx.length?renderVisWithIdx[0].rawIdx:Infinity;
   const loadedCompactionRawIdxs=(!compressionState)?_loadedCompactionMarkerRawIdxs(S.messages):[];
-  const compactionPlacements=_selectCompactionCardPlacements(loadedCompactionRawIdxs,firstRenderedRawIdx);
+  // A loaded marker that matches the current summary already renders as its
+  // own card. When none matches (referenceMessageRawIdx<0) the current summary
+  // is still authoritative and must stay visible even next to stale markers,
+  // so the settled fallback is decided here, before any card node is built,
+  // and takes part in the single preserved-task owner selection.
+  const showCurrentSummaryFallback=!!(!compressionState && referenceMessageRawIdx<0 && _shouldShowSettledCompressionReference(referenceText) && (sessionCompressionAnchor!==null || sessionCompressionAnchorKey || sessionCompressionSummary));
+  const compactionPlacements=_selectCompactionCardPlacements(loadedCompactionRawIdxs,firstRenderedRawIdx,showCurrentSummaryFallback);
+  const referenceNodeOwnsTasks=!!(showCurrentSummaryFallback
+    && compactionPlacements.taskOwner
+    && compactionPlacements.taskOwner.kind==='current-summary'
+    && preservedCompressionTaskMessages.length);
   const _compactionCardEntry=(markerRawIdx,kind)=>{
     const markerMsg=S.messages[markerRawIdx];
     let raw='';
@@ -17098,8 +17114,8 @@ function renderMessages(options){
   };
   const preWindowCompactionCards=compactionPlacements.preWindowMarkers.map(markerRawIdx=>_compactionCardEntry(markerRawIdx,'pre-window'));
   const compactionCardNodes=compactionPlacements.inlineMarkers.map(markerRawIdx=>_compactionCardEntry(markerRawIdx,'inline'));
-  const referenceNode=(!compressionState && loadedCompactionRawIdxs.length===0 && _shouldShowSettledCompressionReference(referenceText) && (sessionCompressionAnchor!==null || sessionCompressionAnchorKey || sessionCompressionSummary))
-    ? (()=>{const row=document.createElement('div');row.innerHTML=`<div class="compression-turn"><div class="compression-turn-blocks">${_compressionReferenceCardHtml(referenceText,false)}${_preservedCompressionTaskListCardsHtml(preservedCompressionTaskMessages)}</div></div>`;const node=row.firstElementChild;if(node&&preservedCompressionTaskMessages.length) node.setAttribute('data-compaction-task-owner','1');return node;})()
+  const referenceNode=showCurrentSummaryFallback
+    ? (()=>{const row=document.createElement('div');row.innerHTML=`<div class="compression-turn"><div class="compression-turn-blocks">${_compressionReferenceCardHtml(referenceText,false)}${referenceNodeOwnsTasks?_preservedCompressionTaskListCardsHtml(preservedCompressionTaskMessages):''}</div></div>`;const node=row.firstElementChild;if(node&&referenceNodeOwnsTasks) node.setAttribute('data-compaction-task-owner','1');return node;})()
     : null;
   let referenceNodePinnedAtTop=false;
   let preservedCompressionTaskOwnerNode=null;
@@ -17142,7 +17158,7 @@ function renderMessages(options){
     // Keep the settled compacted-context card immediately visible in a long,
     // tail-loaded conversation. Put it in flow (not inside an old tool turn).
     referenceNodePinnedAtTop=_pinSettledCompressionReferenceAtTop(inner,referenceNode,referenceMessageRawIdx);
-    if(referenceNodePinnedAtTop&&referenceNode?.parentElement&&preservedCompressionTaskMessages.length){
+    if(referenceNodePinnedAtTop&&referenceNode?.parentElement&&referenceNodeOwnsTasks){
       preservedCompressionTaskOwnerNode=referenceNode;
     }
   }
@@ -17780,7 +17796,7 @@ function renderMessages(options){
     const referenceInserted=referenceNode&&referenceMessageRawIdx>=0
       ?_insertCompressionLikeNodeByRawIdx(referenceNode,referenceMessageRawIdx)
       :_insertCompressionLikeNode(referenceNode);
-    if(referenceInserted&&referenceNode?.parentElement&&preservedCompressionTaskMessages.length){
+    if(referenceInserted&&referenceNode?.parentElement&&referenceNodeOwnsTasks){
       preservedCompressionTaskOwnerNode=referenceNode;
     }
   }

tests/test_auto_compression_card.py

@@ -1079,7 +1079,7 @@ def test_context_anchor_reference_uses_session_summary_fallback():
     assert "const referenceText=(()=>{" in src
     assert "if(!referenceMessage) return sessionCompressionSummary;" in src
     assert "return segment!==null?segment:raw;" in src
-    assert "loadedCompactionRawIdxs.length===0 && _shouldShowSettledCompressionReference(referenceText)" in src
+    assert "referenceMessageRawIdx<0 && _shouldShowSettledCompressionReference(referenceText)" in src
     assert "!_isContextCompactionText(referenceText)" in src
 
 

tests/test_compaction_card_display.py

@@ -136,6 +136,20 @@ assert.deepStrictEqual(
   _selectCompactionCardPlacements([], 50),
   {{preWindowMarkers: [], inlineMarkers: [], taskOwner: null}},
 );
+// A current-summary fallback (no loaded marker matches the session summary)
+// owns the preserved tasks even when stale markers are still loaded.
+assert.deepStrictEqual(
+  _selectCompactionCardPlacements([3, 11, 49, 88], 50, true),
+  {{
+    preWindowMarkers: [3, 11, 49],
+    inlineMarkers: [88],
+    taskOwner: {{kind: 'current-summary', rawIdx: -1}},
+  }},
+);
+assert.deepStrictEqual(
+  _selectCompactionCardPlacements([], 50, true),
+  {{preWindowMarkers: [], inlineMarkers: [], taskOwner: {{kind: 'current-summary', rawIdx: -1}}}},
+);
 """
     _run_node(script)
 

tests/test_compaction_current_summary_fallback.py

@@ -0,0 +1,528 @@
+"""Render-level regression: stale compaction markers must not hide the current summary.
+
+A session can carry historical ``[CONTEXT COMPACTION]`` markers in its loaded
+transcript while ``session.compression_anchor_summary`` already describes a
+newer compaction that no loaded marker references. ``renderMessages()`` must
+still render that current summary as its own settled card (as ``master`` did)
+and the preserved task cards must be attached to exactly one owner.
+
+The scenario drives the real ``renderMessages()`` through the same Node
+harness used by ``tests/test_anchor_fallback_ownership.py``; only the DOM
+shim gains a minimal ``innerHTML`` → ``firstElementChild`` parser so the
+compaction card nodes built by ``renderMessages()`` are real elements.
+"""
+
+from __future__ import annotations
+
+import json
+import textwrap
+
+from tests.test_anchor_fallback_ownership import (
+    _function_source,
+    _run_node_script,
+    _ui_js,
+)
+
+
+_REAL_FUNCTIONS = (
+    "_transparentStreamOrderedParts",
+    "_legacySettledFallbackHasToolMetadata",
+    "_isContextCompactionText",
+    "_isContextCompactionMessage",
+    "_compactionSummarySegment",
+    "_isPreservedCompressionTaskListMarkerText",
+    "_isPreservedCompressionTaskListMessage",
+    "_preservedCompressionTaskListPreview",
+    "_latestTodoToolItems",
+    "_hasActiveTodoItems",
+    "_latestPreservedCompressionTaskListMessages",
+    "_compressionStatusCardHtml",
+    "_preservedCompressionTaskListCardHtml",
+    "_preservedCompressionTaskListCardsHtml",
+    "_latestCompressionReferenceMessage",
+    "_shouldShowSettledCompressionReference",
+    "_compactionDigestText",
+    "_compactionCardPreview",
+    "_compressionReferenceCardHtml",
+    "_loadedCompactionMarkerRawIdxs",
+    "_selectCompactionCardPlacements",
+    "_insertCompactionCardNodes",
+    "_insertPreservedCompressionTaskFallback",
+    "_pinCompactionCardAtTop",
+    "_pinSettledCompressionReferenceAtTop",
+    "renderMessages",
+)
+
+_DOM_SHIM = r"""
+class FakeClassList {
+  constructor(el) { this.el = el; }
+  _set() { return new Set(String(this.el.className || '').split(/\s+/).filter(Boolean)); }
+  contains(name) { return this._set().has(name); }
+  add(...names) {
+    const set = this._set();
+    names.forEach((name) => set.add(name));
+    this.el.className = Array.from(set).join(' ');
+  }
+  remove(...names) {
+    const set = this._set();
+    names.forEach((name) => set.delete(name));
+    this.el.className = Array.from(set).join(' ');
+  }
+  toggle(name) {
+    const set = this._set();
+    if (set.has(name)) set.delete(name); else set.add(name);
+    this.el.className = Array.from(set).join(' ');
+    return set.has(name);
+  }
+}
+function unescapeHtml(value) {
+  return String(value)
+    .replace(/&quot;/g, '"').replace(/&#39;/g, "'").replace(/&lt;/g, '<')
+    .replace(/&gt;/g, '>').replace(/&amp;/g, '&');
+}
+// Minimal HTML → FakeElement tree parser. Only used when renderMessages()
+// reads `firstElementChild` after assigning innerHTML (the compaction /
+// reference / preserved-task card nodes). Text nodes are dropped; the
+// assertions below rely on data-* attributes only.
+function parseHtmlInto(parent, html) {
+  const tagRe = /<(\/)?([A-Za-z][\w-]*)((?:\s+[\w:-]+(?:="[^"]*")?)*)\s*(\/)?>/g;
+  const stack = [parent];
+  let match;
+  while ((match = tagRe.exec(html))) {
+    if (match[1]) {
+      if (stack.length > 1) stack.pop();
+      continue;
+    }
+    const el = new FakeElement(match[2]);
+    const attrRe = /([\w:-]+)(?:="([^"]*)")?/g;
+    let attr;
+    while ((attr = attrRe.exec(match[3] || ''))) {
+      el.setAttribute(attr[1], attr[2] === undefined ? '' : unescapeHtml(attr[2]));
+    }
+    stack[stack.length - 1].appendChild(el);
+    if (!match[4]) stack.push(el);
+  }
+}
+class FakeElement {
+  constructor(tag = 'div') {
+    this.tagName = tag.toUpperCase();
+    this.children = [];
+    this.parentElement = null;
+    this.dataset = {};
+    this.attributes = {};
+    this.className = '';
+    this.id = '';
+    this.hidden = false;
+    this._innerHTML = '';
+    this._pendingHtml = null;
+    this.style = {};
+    this.classList = new FakeClassList(this);
+  }
+  set innerHTML(value) {
+    this._innerHTML = String(value);
+    for (const child of this.children) child.parentElement = null;
+    this.children = [];
+    this._pendingHtml = this._innerHTML ? this._innerHTML : null;
+  }
+  get innerHTML() { return this._innerHTML; }
+  get firstElementChild() {
+    if (this._pendingHtml !== null) {
+      const html = this._pendingHtml;
+      this._pendingHtml = null;
+      parseHtmlInto(this, html);
+    }
+    return this.children[0] || null;
+  }
+  appendChild(child) {
+    if (child.parentElement) child.remove();
+    child.parentElement = this;
+    this.children.push(child);
+    return child;
+  }
+  insertBefore(child, ref) {
+    if (child.parentElement) child.remove();
+    child.parentElement = this;
+    const idx = this.children.indexOf(ref);
+    if (idx < 0) this.children.push(child);
+    else this.children.splice(idx, 0, child);
+    return child;
+  }
+  remove() {
+    if (!this.parentElement) return;
+    const idx = this.parentElement.children.indexOf(this);
+    if (idx >= 0) this.parentElement.children.splice(idx, 1);
+    this.parentElement = null;
+  }
+  setAttribute(name, value) {
+    this.attributes[name] = String(value);
+    if (name === 'id') this.id = String(value);
+    if (name === 'class') this.className = String(value);
+    if (name.startsWith('data-')) this.dataset[dataKey(name)] = String(value);
+  }
+  getAttribute(name) {
+    if (name === 'id') return this.id || null;
+    if (name === 'class') return this.className || null;
+    if (name.startsWith('data-')) {
+      const value = this.dataset[dataKey(name)];
+      return value === undefined ? null : String(value);
+    }
+    return this.attributes[name] === undefined ? null : this.attributes[name];
+  }
+  removeAttribute(name) {
+    delete this.attributes[name];
+    if (name.startsWith('data-')) delete this.dataset[dataKey(name)];
+  }
+  matches(selector) { return matchesSelector(this, selector); }
+  closest(selector) {
+    let node = this;
+    while (node) {
+      if (matchesSelector(node, selector)) return node;
+      node = node.parentElement;
+    }
+    return null;
+  }
+  querySelectorAll(selector) {
+    const found = [];
+    const visit = (node) => {
+      for (const child of node.children) {
+        if (matchesSelector(child, selector)) found.push(child);
+        visit(child);
+      }
+    };
+    visit(this);
+    return found;
+  }
+  querySelector(selector) {
+    return this.querySelectorAll(selector)[0] || null;
+  }
+  insertAdjacentHTML() {}
+}
+function dataKey(name) {
+  return String(name).slice(5).replace(/-([a-z])/g, (_, c) => c.toUpperCase());
+}
+function matchesSelector(el, selector) {
+  return String(selector || '').split(',').some((part) => matchesSimple(el, part.trim()));
+}
+function matchesSimple(el, selector) {
+  if (!selector) return false;
+  const negated = [];
+  const baseSelector = selector.replace(/:not\(([^()]*)\)/g, (_, inner) => {
+    negated.push(String(inner || '').trim());
+    return '';
+  }).trim();
+  if (negated.some((inner) => inner && matchesSimple(el, inner))) return false;
+  if (!baseSelector) return true;
+  const classMatches = [...baseSelector.matchAll(/\.([A-Za-z0-9_-]+)/g)].map((m) => m[1]);
+  if (classMatches.some((name) => !el.classList.contains(name))) return false;
+  const attrMatches = [...baseSelector.matchAll(/\[([^=\]]+)(?:=["']?([^"'\]]+)["']?)?\]/g)];
+  for (const match of attrMatches) {
+    const value = el.getAttribute(match[1]);
+    if (value === null) return false;
+    if (match[2] !== undefined && String(value) !== String(match[2])) return false;
+  }
+  const idMatch = baseSelector.match(/#([A-Za-z0-9_-]+)/);
+  if (idMatch && el.id !== idMatch[1]) return false;
+  const tagMatch = baseSelector.match(/^[A-Za-z][A-Za-z0-9_-]*/);
+  if (tagMatch && el.tagName.toLowerCase() !== tagMatch[0].toLowerCase()) return false;
+  return true;
+}
+
+const elements = {
+  msgInner: new FakeElement('div'),
+  emptyState: new FakeElement('div'),
+};
+global.window = {};
+global.document = {
+  createElement: (tag) => new FakeElement(tag),
+  getElementById: (id) => elements[id] || null,
+};
+global.performance = { now: () => 1 };
+global.requestAnimationFrame = (fn) => fn();
+global.setTimeout = (fn) => fn();
+function $(id) { return elements[id] || null; }
+function isTransparentStream() { return false; }
+function isCompactWorklogMode() { return true; }
+function isSimplifiedToolCalling() { return true; }
+function t(key) { return key; }
+function li() { return ''; }
+function esc(value) {
+  return String(value == null ? '' : value)
+    .replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;').replace(/"/g, '&quot;');
+}
+function msgContent(message) {
+  if (Array.isArray(message.content)) {
+    return message.content.filter((p) => p && p.type === 'text').map((p) => p.text || p.content || '').join('\n');
+  }
+  return String(message.content || '');
+}
+let S;
+const INFLIGHT = {};
+let _loadingSessionId = null;
+let _messageRenderWindowSid = null;
+let _messageUserUnpinned = false;
+let _programmaticScroll = false;
+let _programmaticScrollSetAt = 0;
+let _sessionHtmlCacheSid = null;
+let _messagesTruncated = false;
+let _oldestIdx = 0;
+let virtualStart = 0;
+const _sessionHtmlCache = new Map();
+const _recycleStash = new Map();
+const _msgNodeRecycleEnabled = false;
+const _recycleResetAttrs = [];
+const _ERR_MSG_RE = /__never__/;
+
+function _captureMessageScrollSnapshot() { return null; }
+function _resetMessageRenderWindow(sid) { _messageRenderWindowSid = sid; }
+function _getVisibleMessagesWithIdx() {
+  return S.messages.map((m, rawIdx) => (
+    m && m.role !== 'tool' && !_isContextCompactionMessage(m) && !_isPreservedCompressionTaskListMessage(m)
+  ) ? { m, rawIdx } : null).filter(Boolean);
+}
+function _messageVirtualKeepTailCount() { return 20; }
+function _currentMessageVirtualWindow(vis) {
+  const start = Math.min(virtualStart, vis.length);
+  return {
+    virtualized: start > 0,
+    start,
+    end: vis.length,
+    topPad: start > 0 ? 120 * start : 0,
+    bottomPad: 0,
+    total: vis.length,
+    tailStart: vis.length,
+  };
+}
+function _messageVirtualWindowKeyFor() { return 'all'; }
+function _messageRenderCacheSignature() { return 'sig'; }
+function _compressionStateForCurrentSession() { return null; }
+function clearCompressionUi() {}
+function _handoffStateForCurrentSession() { return null; }
+function _captureWorklogDetailDisclosureState() { return null; }
+function _applySessionNavigationPrefs() {}
+function _messageVirtualSpacer() { return new FakeElement('div'); }
+function _wireMessageWindowLoadEarlierButton() {}
+function _compressionAnchorIndex() { return null; }
+function _assistantTurnFinalVisibleContentMap() { return new Map(); }
+function _assistantTurnVisibleContentMap() { return new Map(); }
+function _engineAwareCompressionCopy() {
+  return { label: 'context_compaction_label', preview: 'reference_only_label' };
+}
+function _createAssistantTurn() {
+  const turn = new FakeElement('div');
+  turn.className = 'assistant-turn';
+  const blocks = new FakeElement('div');
+  blocks.className = 'assistant-turn-blocks';
+  turn.appendChild(blocks);
+  return turn;
+}
+function _assistantTurnBlocks(turn) { return turn ? turn.querySelector('.assistant-turn-blocks') : null; }
+function _setLatestAssistantTurnLandmark() {}
+function _assistantRoleHtml() { return ''; }
+function _userMessageDomId(rawIdx) { return `user-${rawIdx}`; }
+function _messageSessionIndexForRawIdx(rawIdx) { return rawIdx; }
+function _messageViewportAnchorKeyForMessage() { return 'k'; }
+function _stripAttachedFilesMarkerForDisplay(value) { return String(value || ''); }
+function _stripWorkspaceDisplayPrefix(value) { return String(value || ''); }
+function _stripLeadingAssistantThinkingMarkup(value) { return String(value || ''); }
+function _getCachedRender(value) { return String(value || ''); }
+function _formatInServerTz() { return ''; }
+function _formatMessageFooterTimestamp() { return ''; }
+function _questionJumpButtonHtml() { return ''; }
+function _formatTurnTps() { return ''; }
+function isTpsDisplayEnabled() { return false; }
+function _renderAttachmentHtml() { return ''; }
+function _isMarkerOnlyAssistantCompressionMessage() { return false; }
+function _isAssistantEmptyPlaceholderContent() { return false; }
+function _assistantTurnAnchorSettledFinalAnswer() { return null; }
+function _worklogReasoningTextFromMessage() { return ''; }
+function _assistantMessageBelongsInWorklog() { return false; }
+function _assistantThinkingBelongsInWorklog() { return false; }
+function _assistantReasoningPayloadText() { return ''; }
+function _statusCardHtml() { return ''; }
+function _collectHandoffSummaryStates() { return []; }
+function _handoffCardsNode() { return null; }
+function renderCompressionUi() {}
+function _assistantToolAnchorIdxForMessage(messages, rawIdx) { return rawIdx; }
+function _cliToolResultSnippet(value) { return String(value || ''); }
+function _cliPatchSnippetFromArgs() { return ''; }
+function _cliToolCardSnippet(value) { return String(value || ''); }
+function _cliToolCardHasDiffSnippet() { return false; }
+function _toolArgsSnapshot(args) { return args || {}; }
+function _worklogReasonHtmlFromAnchor() { return ''; }
+function _normalizeThinkingEchoCompare(value) { return String(value || ''); }
+function _toolWorklogListEl(group) { return group; }
+function ensureActivityGroup(parent) {
+  const group = new FakeElement('div');
+  if (parent) parent.appendChild(group);
+  return group;
+}
+function _appendWorklogStep() {}
+function _syncToolCallGroupSummary() {}
+function _restoreWorklogDetailDisclosureState() {}
+function _scrollAfterMessageRender() {}
+function _maybeRecoverVirtualizedBlankViewport() { return false; }
+function _updateMessageVirtualMeasurements() {}
+function postProcessRenderedMessages() {}
+function _postProcessWithAnchorSuppression() {}
+function _formatGatewayModelLabel() { return ''; }
+function _gatewayRoutingFailoverText() { return ''; }
+function _gatewayModelWarningText() { return ''; }
+function _usedModelTurnChipLabel() { return ''; }
+function _formatTurnDuration() { return ''; }
+function _renderSettledAnchorSceneForMessage() { return false; }
+"""
+
+_SCENARIO = r"""
+const TOTAL = 220;
+const STALE_MARKER_IDXS = [40, 100, 160];
+const TASK_LIST_IDX = 161;
+const CURRENT_TOKEN = 'CURRENT-SUMMARY-TOKEN-7124';
+const TASK_MARKER = '[Your active task list was preserved across context compression]';
+
+function staleMarker(rawIdx) {
+  return '[CONTEXT COMPACTION — REFERENCE ONLY] Earlier turns were compacted into the summary below.\n'
+    + '## Historical Task Snapshot\nUser asked: "stale request ' + rawIdx + '"\n'
+    + '## Goal\nSTALE-MARKER-' + rawIdx + ' historical state\n--- END OF CONTEXT SUMMARY ---';
+}
+function buildMessages() {
+  const messages = [];
+  for (let i = 0; i < TOTAL; i++) {
+    if (STALE_MARKER_IDXS.includes(i)) {
+      messages.push({ role: 'assistant', content: staleMarker(i) });
+    } else if (i === TASK_LIST_IDX) {
+      messages.push({ role: 'user', content: TASK_MARKER + '\n- [ ] finish the compaction fix' });
+    } else if (i % 2 === 0) {
+      messages.push({ role: 'user', content: 'question ' + i });
+    } else {
+      messages.push({ role: 'assistant', content: 'answer ' + i });
+    }
+  }
+  return messages;
+}
+function render(opts) {
+  elements.msgInner = new FakeElement('div');
+  _sessionHtmlCache.clear();
+  _sessionHtmlCacheSid = null;
+  virtualStart = opts.virtualStart || 0;
+  _messagesTruncated = !!opts.truncated;
+  _oldestIdx = opts.truncated ? 50 : 0;
+  S = {
+    session: {
+      session_id: opts.sid,
+      compression_anchor_summary: opts.summary,
+    },
+    messages: buildMessages(),
+    toolCalls: [],
+    busy: false,
+  };
+  renderMessages();
+  const inner = elements.msgInner;
+  const cards = inner.querySelectorAll('[data-compression-card]');
+  const rawText = (node) => String(node.getAttribute('data-raw-text') || '');
+  const summaryCards = cards.filter((node) => rawText(node).includes(CURRENT_TOKEN));
+  const taskCards = cards.filter((node) => rawText(node).startsWith(TASK_MARKER));
+  const owners = inner.querySelectorAll('[data-compaction-task-owner]');
+  const ownerHasSummary = owners.length === 1
+    && owners[0].querySelectorAll('[data-compression-card]').some((node) => rawText(node).includes(CURRENT_TOKEN));
+  const ownerHasTask = owners.length === 1
+    && owners[0].querySelectorAll('[data-compression-card]').some((node) => rawText(node).startsWith(TASK_MARKER));
+  const placements = inner.querySelectorAll('[data-compaction-placement]');
+  const summaryTopIdx = summaryCards.length
+    ? inner.children.findIndex((child) => child.querySelectorAll('[data-compression-card]').some((node) => rawText(node).includes(CURRENT_TOKEN)))
+    : -1;
+  const loadOlderIdx = inner.children.findIndex((child) => child.id === 'loadOlderIndicator');
+  return {
+    renderedRows: inner.querySelectorAll('[data-msg-idx]').length,
+    currentSummaryVisible: summaryCards.length > 0,
+    currentSummaryCards: summaryCards.length,
+    staleCards: placements.map((node) => node.getAttribute('data-compaction-placement')),
+    staleCardTexts: placements.map((node) => {
+      const card = node.querySelector('[data-compression-card]');
+      return card ? (/STALE-MARKER-(\d+)/.exec(rawText(card))?.[1] || null) : null;
+    }),
+    taskCards: taskCards.length,
+    taskOwners: owners.length,
+    ownerHasSummary,
+    ownerHasTask,
+    standaloneFallbacks: inner.querySelectorAll('[data-compaction-task-fallback]').length,
+    summaryTopIdx,
+    loadOlderIdx,
+  };
+}
+
+const NEWER_SUMMARY = 'Compacted context: ' + CURRENT_TOKEN + ' — newest state after the last compaction';
+const fullWindow = render({ sid: 'full', summary: NEWER_SUMMARY });
+// Visible index 170 maps to raw idx >= 174 (three markers and the task-list
+// message are not renderable rows), so every stale marker is pre-window.
+const virtualWindow = render({ sid: 'virtual', summary: NEWER_SUMMARY, virtualStart: 170 });
+const truncatedTail = render({ sid: 'truncated', summary: NEWER_SUMMARY, truncated: true });
+// Control: the current summary IS referenced by the latest loaded marker, so
+// the marker card renders it and no second (fallback) card may appear.
+const matchingSummary = render({ sid: 'matching', summary: 'STALE-MARKER-160 historical state' });
+const matchingCards = elements.msgInner.querySelectorAll('[data-compression-card]')
+  .filter((node) => String(node.getAttribute('data-raw-text') || '').includes('STALE-MARKER-160'));
+console.log(JSON.stringify({
+  fullWindow,
+  virtualWindow,
+  truncatedTail,
+  matchingSummary: {
+    ...matchingSummary,
+    latestMarkerCards: matchingCards.length,
+  },
+}));
+"""
+
+
+def _scenario_script() -> str:
+    js = _ui_js()
+    evals = "\n".join(
+        f"eval({json.dumps(_function_source(js, name))});" for name in _REAL_FUNCTIONS
+    )
+    return textwrap.dedent(_DOM_SHIM) + "\n" + evals + "\n" + textwrap.dedent(_SCENARIO)
+
+
+def test_stale_markers_do_not_suppress_current_summary_and_task_owner_is_unique():
+    result = json.loads(_run_node_script(_scenario_script()))
+
+    full = result["fullWindow"]
+    assert full["renderedRows"] > 200
+    assert full["currentSummaryVisible"] is True
+    assert full["currentSummaryCards"] == 1
+    assert full["staleCards"] == ["inline", "inline", "inline"]
+    assert full["staleCardTexts"] == ["40", "100", "160"]
+    assert full["taskCards"] == 1
+    assert full["taskOwners"] == 1
+    assert full["ownerHasSummary"] is True
+    assert full["ownerHasTask"] is True
+    assert full["standaloneFallbacks"] == 0
+
+    virtual = result["virtualWindow"]
+    assert virtual["currentSummaryVisible"] is True
+    assert virtual["currentSummaryCards"] == 1
+    assert virtual["staleCards"] == ["pre-window", "pre-window", "pre-window"]
+    assert virtual["staleCardTexts"] == ["40", "100", "160"]
+    assert virtual["taskCards"] == 1
+    assert virtual["taskOwners"] == 1
+    assert virtual["ownerHasSummary"] is True
+    assert virtual["standaloneFallbacks"] == 0
+
+    truncated = result["truncatedTail"]
+    assert truncated["currentSummaryVisible"] is True
+    assert truncated["currentSummaryCards"] == 1
+    assert truncated["loadOlderIdx"] >= 0
+    # The settled current-summary card is pinned directly under the
+    # load-earlier affordance, before the stale marker cards and rows.
+    assert truncated["summaryTopIdx"] == truncated["loadOlderIdx"] + 1
+    assert truncated["taskCards"] == 1
+    assert truncated["taskOwners"] == 1
+    assert truncated["ownerHasSummary"] is True
+    assert truncated["standaloneFallbacks"] == 0
+
+    matching = result["matchingSummary"]
+    assert matching["currentSummaryVisible"] is False
+    assert matching["latestMarkerCards"] == 1
+    assert matching["staleCards"] == ["inline", "inline", "inline"]
+    assert matching["taskCards"] == 1
+    assert matching["taskOwners"] == 1
+    assert matching["ownerHasTask"] is True
+    assert matching["standaloneFallbacks"] == 0