diff --git a/packages/kilo-ui/src/components/diff.tsx b/packages/kilo-ui/src/components/diff.tsx
index cee9fba7a4..7b308640e1 100644
--- a/packages/kilo-ui/src/components/diff.tsx
+++ b/packages/kilo-ui/src/components/diff.tsx
@@ -56,14 +56,21 @@ function enqueue(job: Job) {
   schedule()
 }
 
-// When a large batch of diffs becomes near-visible at once, render one diff per
-// animation frame. This keeps the UI responsive while preserving expanded state.
+const FRAME_BUDGET_MS = 12
+
+// When a batch of diffs becomes near-visible at once, render within a per-frame
+// time budget so visible diffs populate smoothly in the same frame while preserving
+// 60fps responsiveness for large lists.
 function schedule() {
   if (frame !== undefined) return
   frame = requestAnimationFrame(() => {
     frame = undefined
-    const job = queue.shift()
-    if (job && !job.cancelled) job.run()
+    const deadline = performance.now() + FRAME_BUDGET_MS
+    while (queue.length > 0) {
+      const job = queue.shift()
+      if (job && !job.cancelled) job.run()
+      if (performance.now() >= deadline) break
+    }
     if (queue.length > 0) schedule()
   })
 }
diff --git a/packages/kilo-vscode/tests/unit/prompt-send-contract.test.ts b/packages/kilo-vscode/tests/unit/prompt-send-contract.test.ts
index f94736a960..fe4da953db 100644
--- a/packages/kilo-vscode/tests/unit/prompt-send-contract.test.ts
+++ b/packages/kilo-vscode/tests/unit/prompt-send-contract.test.ts
@@ -589,6 +589,29 @@ describe("Cloud import parts cleanup contract", () => {
   })
 })
 
+describe("Optimistic parts preservation and smooth status contract", () => {
+  const source = readFile(SESSION_FILE)
+
+  it("handleMessageCreated preserves optimistic parts instead of deleting them", () => {
+    const created = extractFunctionBody(source, "handleMessageCreated")
+    expect(created).not.toMatch(/delete\s+p\[message\.id\]/)
+    expect(created).toContain("pendingOptimistic.get(message.sessionID)")
+  })
+
+  it("handlePartUpdated replaces matching optimistic parts in place", () => {
+    const updated = extractFunctionBody(source, "handlePartUpdated")
+    expect(updated).toContain("pendingOptimisticParts.get(effectiveMessageID)")
+    expect(updated).toContain("optIds.delete")
+  })
+
+  it("statusText derives status only from the active turn after the last user message", () => {
+    const match = source.match(/const statusText = createMemo<string \| undefined>\(\(\) => \{([\s\S]*?)\n  \}\)/)
+    expect(match).not.toBeNull()
+    expect(match![1]).toContain('msgs.findLastIndex((m) => m.role === "user")')
+    expect(match![1]).toContain('language.t("ui.sessionTurn.status.thinking")')
+  })
+})
+
 describe("KiloConnectionService pruneSession contract", () => {
   const source = readFile(CONNECTION_SERVICE_FILE)
 
diff --git a/packages/kilo-vscode/tests/unit/session-queue.test.ts b/packages/kilo-vscode/tests/unit/session-queue.test.ts
index 77f8ae6a29..349f7dac07 100644
--- a/packages/kilo-vscode/tests/unit/session-queue.test.ts
+++ b/packages/kilo-vscode/tests/unit/session-queue.test.ts
@@ -101,11 +101,41 @@ describe("queuedUserMessageIDs", () => {
     expect(queuedUserMessageIDs(messages, { type: "busy" })).toEqual(["message_3"])
   })
 
-  it("returns no queued messages while idle", () => {
+  it("returns no queued messages while idle without submitting flag", () => {
     const messages = [user("message_1"), user("message_2")]
 
     expect(queuedUserMessageIDs(messages, { type: "idle" })).toEqual([])
   })
+
+  it("queues follow-ups while idle when submitting is true", () => {
+    const messages = [user("message_1"), user("message_2")]
+
+    expect(queuedUserMessageIDs(messages, { type: "idle" }, undefined, true)).toEqual(["message_2"])
+  })
+})
+
+describe("activeUserMessageID", () => {
+  it("returns undefined while idle and not submitting", () => {
+    const messages = [user("message_1")]
+
+    expect(activeUserMessageID(messages, { type: "idle" })).toBeUndefined()
+  })
+
+  it("returns the pending user message while idle when submitting is true", () => {
+    const messages = [user("message_1")]
+
+    expect(activeUserMessageID(messages, { type: "idle" }, undefined, true)).toBe("message_1")
+  })
+
+  it("returns the next pending user message after finished turn when submitting is true", () => {
+    const messages = [
+      user("message_1"),
+      assistant("message_2", "message_1", { finish: "stop", time: { created: 1, completed: 2 } }),
+      user("message_3"),
+    ]
+
+    expect(activeUserMessageID(messages, { type: "idle" }, undefined, true)).toBe("message_3")
+  })
 })
 
 describe("partitionTurns", () => {
diff --git a/packages/kilo-vscode/webview-ui/agent-manager/DiffPanel.tsx b/packages/kilo-vscode/webview-ui/agent-manager/DiffPanel.tsx
index ae15fa3cf6..ef83c00fcd 100644
--- a/packages/kilo-vscode/webview-ui/agent-manager/DiffPanel.tsx
+++ b/packages/kilo-vscode/webview-ui/agent-manager/DiffPanel.tsx
@@ -132,7 +132,21 @@ export const DiffPanel: Component<DiffPanelProps> = (props) => {
   })
   const localComposer = createReviewComposer()
   const composer = () => props.composer ?? localComposer
-  const [open, setOpen] = createSignal<string[]>([])
+  const [manualOpen, setManualOpen] = createSignal<Record<string, string[]>>({})
+  const open = createMemo(() => {
+    const key = props.sessionKey ?? ""
+    const diffs = props.diffs
+    if (diffs.length === 0) return []
+    const manual = manualOpen()[key]
+    if (manual) return sanitizeOpenFiles(diffs, manual)
+    return initialOpenFiles(diffs)
+  })
+  const setOpen = (files: string[] | ((prev: string[]) => string[])) => {
+    const key = props.sessionKey ?? ""
+    const current = open()
+    const next = typeof files === "function" ? files(current) : files
+    setManualOpen((prev) => ({ ...prev, [key]: sanitizeOpenFiles(props.diffs, next) }))
+  }
   const [draft, setDraft] = createSignal<ReviewDraft | null>(reviewComposerDraft(composer()))
   const [editing, setEditing] = createSignal<string | null>(reviewComposerEdit(composer()))
   const speechKeys = createMemo(() => {
@@ -151,10 +165,6 @@ export const DiffPanel: Component<DiffPanelProps> = (props) => {
     keys: speechKeys,
   })
   let nextId = 0
-  // Initialize each worktree with every file expanded, then preserve manual
-  // collapse state while adding and removing files from live summaries.
-  let initializedKey: string | undefined
-  let known = new Set<string>()
 
   // Reorder diffs to match the file-tree's depth-first visual order so
   // scrolling through the accordion matches the tree grouping.
@@ -217,43 +227,6 @@ export const DiffPanel: Component<DiffPanelProps> = (props) => {
     focusRoot()
   }
 
-  // Unified open-state effect: tracks both sessionKey and diffs in a single effect
-  // to eliminate the race condition between the old separate sessionKey-reset and
-  // diffs-watch effects. Uses the session key to decide when initialization is needed
-  // vs when we just prune stale entries from the open list.
-  createEffect(
-    on(
-      () => [props.sessionKey, props.diffs] as const,
-      ([key, diffs]) => {
-        // No diffs yet (async fetch in progress) — don't mark as initialized
-        // so auto-open runs when data arrives.
-        // Important: do not prune on empty, otherwise transient empty updates
-        // collapse all files and they stay collapsed for the same key.
-        if (diffs.length === 0) return
-
-        const fileSet = new Set(diffs.map((diff) => diff.file))
-
-        // New context: initialize open state from the diff policy.
-        if (key !== initializedKey) {
-          initializedKey = key
-          known = fileSet
-          setOpen(initialOpenFiles(diffs))
-          return
-        }
-
-        // Preserve manual collapse state for known files, while keeping newly
-        // arriving files expanded when a live summary grows.
-        const added = diffs.filter((diff) => !known.has(diff.file)).map((diff) => diff.file)
-        known = fileSet
-        setOpen((prev) => {
-          const next = sanitizeOpenFiles(diffs, [...prev.filter((file) => fileSet.has(file)), ...added])
-          if (next.length === prev.length && next.every((file, index) => file === prev[index])) return prev
-          return next
-        })
-      },
-    ),
-  )
-
   createEffect(
     on(
       () => props.sessionKey,
diff --git a/packages/kilo-vscode/webview-ui/diff-viewer/FullScreenDiffView.tsx b/packages/kilo-vscode/webview-ui/diff-viewer/FullScreenDiffView.tsx
index 6f708f8bd9..d35b8f95b0 100644
--- a/packages/kilo-vscode/webview-ui/diff-viewer/FullScreenDiffView.tsx
+++ b/packages/kilo-vscode/webview-ui/diff-viewer/FullScreenDiffView.tsx
@@ -134,7 +134,36 @@ export const FullScreenDiffView: Component<FullScreenDiffViewProps> = (props) =>
   })
   const localComposer = createReviewComposer()
   const composer = () => props.composer ?? localComposer
-  const [open, setOpen] = createSignal<string[]>([])
+  const [manualOpen, setManualOpen] = createSignal<Record<string, string[]>>({})
+  const open = createMemo(() => {
+    const key = props.sessionKey ?? ""
+    const diffs = props.diffs
+    if (diffs.length === 0) return []
+    const manual = manualOpen()[key]
+    if (manual) return sanitizeOpenFiles(diffs, manual)
+    return initialOpenFiles(diffs)
+  })
+  const setOpen = (files: string[] | ((prev: string[]) => string[])) => {
+    const key = props.sessionKey ?? ""
+    const current = open()
+    const next = typeof files === "function" ? files(current) : files
+    setManualOpen((prev) => ({ ...prev, [key]: sanitizeOpenFiles(props.diffs, next) }))
+  }
+
+  const [manualActiveFile, setManualActiveFile] = createSignal<Record<string, string | null>>({})
+  const activeFile = createMemo(() => {
+    const key = props.sessionKey ?? ""
+    const diffs = props.diffs
+    if (diffs.length === 0) return null
+    const manual = manualActiveFile()[key]
+    if (manual && diffs.some((d) => d.file === manual)) return manual
+    return diffs[0]?.file ?? null
+  })
+  const setActiveFile = (file: string | null) => {
+    const key = props.sessionKey ?? ""
+    setManualActiveFile((prev) => ({ ...prev, [key]: file }))
+  }
+
   const [draft, setDraft] = createSignal<ReviewDraft | null>(reviewComposerDraft(composer()))
   const [editing, setEditing] = createSignal<string | null>(reviewComposerEdit(composer()))
   const speechKeys = createMemo(() => {
@@ -152,15 +181,10 @@ export const FullScreenDiffView: Component<FullScreenDiffViewProps> = (props) =>
     label: t,
     keys: speechKeys,
   })
-  const [activeFile, setActiveFile] = createSignal<string | null>(null)
   const [treeWidth, setTreeWidth] = createSignal(240)
   let nextId = 0
   let draftMeta: AnnotationMeta | null = composer().draft
   let editMeta: AnnotationMeta | null = composer().edit
-  // Initialize each worktree with every file expanded, then preserve manual
-  // collapse state while adding and removing files from live summaries.
-  let initializedKey: string | undefined
-  let known = new Set<string>()
   let rootRef: HTMLDivElement | undefined
   const [scroller, setScroller] = createSignal<HTMLDivElement>()
   const [virtualizer, setVirtualizer] = createSignal<VirtualizerHandle>()
@@ -214,50 +238,6 @@ export const FullScreenDiffView: Component<FullScreenDiffViewProps> = (props) =>
     focusRoot()
   }
 
-  // Unified open-state effect: tracks both sessionKey and diffs in a single effect
-  // to eliminate the race condition between the old separate sessionKey-reset and
-  // diffs-watch effects. Uses the session key to decide when initialization is needed
-  // vs when we just prune stale entries from the open list.
-  createEffect(
-    on(
-      () => [props.sessionKey, props.diffs] as const,
-      ([key, diffs]) => {
-        if (diffs.length === 0) {
-          // No diffs yet — clear active file only for a new key; keep current
-          // selection for transient empty updates in the same key.
-          if (key !== initializedKey) setActiveFile(null)
-          return
-        }
-
-        const fileSet = new Set(diffs.map((diff) => diff.file))
-
-        // Keep active file in sync — pick first if current is stale
-        const current = activeFile()
-        if (!current || !diffs.some((d) => d.file === current)) {
-          setActiveFile(diffs[0]!.file)
-        }
-
-        // New context: initialize open state from the diff policy.
-        if (key !== initializedKey) {
-          initializedKey = key
-          known = fileSet
-          setOpen(initialOpenFiles(diffs))
-          return
-        }
-
-        // Preserve manual collapse state for known files, while keeping newly
-        // arriving files expanded when a live summary grows.
-        const added = diffs.filter((diff) => !known.has(diff.file)).map((diff) => diff.file)
-        known = fileSet
-        setOpen((prev) => {
-          const next = sanitizeOpenFiles(diffs, [...prev.filter((file) => fileSet.has(file)), ...added])
-          if (next.length === prev.length && next.every((file, index) => file === prev[index])) return prev
-          return next
-        })
-      },
-    ),
-  )
-
   createEffect(
     on(
       () => props.sessionKey,
diff --git a/packages/kilo-vscode/webview-ui/src/components/chat/MessageList.tsx b/packages/kilo-vscode/webview-ui/src/components/chat/MessageList.tsx
index e5aa67b906..cd790fda4e 100644
--- a/packages/kilo-vscode/webview-ui/src/components/chat/MessageList.tsx
+++ b/packages/kilo-vscode/webview-ui/src/components/chat/MessageList.tsx
@@ -179,10 +179,23 @@ export const MessageList: Component<MessageListProps> = (props) => {
   const isEmpty = () => turns().length === 0 && !session.loading() && !revert()
 
   const activeUserID = createMemo(() =>
-    getActiveUserMessageID(session.messages(), session.statusInfo(), (msg) => session.getParts(msg.id)),
+    getActiveUserMessageID(
+      session.messages(),
+      session.statusInfo(),
+      (msg) => session.getParts(msg.id),
+      session.submitting(),
+    ),
   )
   const queuedIDs = createMemo(
-    () => new Set(queuedUserMessageIDs(session.messages(), session.statusInfo(), (msg) => session.getParts(msg.id))),
+    () =>
+      new Set(
+        queuedUserMessageIDs(
+          session.messages(),
+          session.statusInfo(),
+          (msg) => session.getParts(msg.id),
+          session.submitting(),
+        ),
+      ),
   )
   const rows = createMemo((prev: TranscriptRow[] | undefined) => {
     const active = activeUserID()
diff --git a/packages/kilo-vscode/webview-ui/src/context/session-queue.ts b/packages/kilo-vscode/webview-ui/src/context/session-queue.ts
index 59b7833551..61a73eecbe 100644
--- a/packages/kilo-vscode/webview-ui/src/context/session-queue.ts
+++ b/packages/kilo-vscode/webview-ui/src/context/session-queue.ts
@@ -198,10 +198,11 @@ export function activeUserMessageID(
   messages: Message[],
   status: SessionStatusInfo,
   parts?: (msg: Message) => Message["parts"],
+  submitting?: boolean,
 ) {
   const id = active(messages, status, parts)
   if (id) return id
-  if (status.type === "idle") return undefined
+  if (status.type === "idle" && !submitting) return undefined
   return pending(messages, parts)
 }
 
@@ -209,8 +210,9 @@ export function queuedUserMessageIDs(
   messages: Message[],
   status: SessionStatusInfo,
   parts?: (msg: Message) => Message["parts"],
+  submitting?: boolean,
 ) {
-  if (status.type === "idle") return []
+  if (status.type === "idle" && !submitting) return []
   const users = messages.filter((msg) => msg.role === "user")
   const running = active(messages, status, parts)
   if (running) {
diff --git a/packages/kilo-vscode/webview-ui/src/context/session-utils.ts b/packages/kilo-vscode/webview-ui/src/context/session-utils.ts
index 218f456026..0ee8ab1578 100644
--- a/packages/kilo-vscode/webview-ui/src/context/session-utils.ts
+++ b/packages/kilo-vscode/webview-ui/src/context/session-utils.ts
@@ -1,5 +1,5 @@
 import { reconcile } from "solid-js/store"
-import type { Message, Part, ToolPart } from "../types/messages"
+import type { Message, MessageLoadMode, Part, ToolPart } from "../types/messages"
 
 export const SNAPSHOT_PROGRESS_TEXT = "Initializing snapshot..."
 
@@ -458,3 +458,27 @@ export function collapseCostBreakdown(
   const aggregated = hidden.reduce((sum, e) => sum + e.cost, 0)
   return [root, ...visible, { label: summaryLabel(hidden.length), cost: aggregated }]
 }
+
+export function mergeMessages(current: Message[], incoming: Message[], mode: Exclude<MessageLoadMode, "focus">) {
+  if (mode === "reconcile") {
+    const byId = new Map<string, Message>()
+    for (const msg of current) byId.set(msg.id, msg)
+    for (const msg of incoming) byId.set(msg.id, msg)
+    return [...byId.values()].sort((a, b) => new Date(a.createdAt).getTime() - new Date(b.createdAt).getTime())
+  }
+  const seen = new Set<string>()
+  const source = mode === "prepend" ? [...incoming, ...current] : incoming
+  return source.filter((msg) => {
+    if (seen.has(msg.id)) return false
+    seen.add(msg.id)
+    return true
+  })
+}
+
+export function messageParts(messages: Message[]): Record<string, Part[]> {
+  const parts: Record<string, Part[]> = {}
+  for (const msg of messages) {
+    if (msg.parts && msg.parts.length > 0) parts[msg.id] = msg.parts
+  }
+  return parts
+}
diff --git a/packages/kilo-vscode/webview-ui/src/context/session.tsx b/packages/kilo-vscode/webview-ui/src/context/session.tsx
index 8831d7edfb..1d95663d8d 100644
--- a/packages/kilo-vscode/webview-ui/src/context/session.tsx
+++ b/packages/kilo-vscode/webview-ui/src/context/session.tsx
@@ -61,6 +61,8 @@ import {
   buildCostBreakdown,
   buildSessionToolParts,
   childID,
+  mergeMessages,
+  messageParts,
   reconcileSessionToolParts,
   removeSessionToolPart,
   removeSessionToolPartsForMessage,
@@ -473,6 +475,7 @@ export const SessionProvider: ParentComponent = (props) => {
   // Tracks optimistic messageIDs that haven't been confirmed by the server yet.
   // Prevents handleMessagesLoaded from wiping them when it replaces the array.
   const pendingOptimistic = new Map<string, Set<string>>()
+  const pendingOptimisticParts = new Map<string, Set<string>>()
   // Sessions can be created/imported while an older list request is still in flight.
   // Keep them until a later list payload confirms them or deletion arrives.
   const freshSessions = new Set<string>()
@@ -1380,28 +1383,6 @@ export const SessionProvider: ParentComponent = (props) => {
     setPages(sessionID, { ...(pages[sessionID] ?? emptyPageState), ...patch })
   }
 
-  function mergeMessages(current: Message[], incoming: Message[], mode: Exclude<MessageLoadMode, "focus">) {
-    if (mode === "reconcile") {
-      // Tail reconcile: incoming is the authoritative newest-N snapshot.
-      // Local state may already hold some of those IDs and may also hold
-      // newer optimistic entries created after the fetch was taken. Merge
-      // by id (server wins on collision) then sort by createdAt so new
-      // server messages land in the right position and optimistic tail
-      // entries stay at the end.
-      const byId = new Map<string, Message>()
-      for (const msg of current) byId.set(msg.id, msg)
-      for (const msg of incoming) byId.set(msg.id, msg)
-      return [...byId.values()].sort((a, b) => new Date(a.createdAt).getTime() - new Date(b.createdAt).getTime())
-    }
-    const seen = new Set<string>()
-    const source = mode === "prepend" ? [...incoming, ...current] : incoming
-    return source.filter((msg) => {
-      if (seen.has(msg.id)) return false
-      seen.add(msg.id)
-      return true
-    })
-  }
-
   function recoverPrefs(sessionID: string, messages: Message[], names = agentNames()) {
     const prefs = resolveMessagePrefs(messages, names)
     if (prefs.agent && !store.agentSelections[sessionID]) {
@@ -1451,14 +1432,6 @@ export const SessionProvider: ParentComponent = (props) => {
     setTools(sessionID, tools)
   }
 
-  function messageParts(messages: Message[]): Record<string, Part[]> {
-    const parts: Record<string, Part[]> = {}
-    for (const msg of messages) {
-      if (msg.parts && msg.parts.length > 0) parts[msg.id] = msg.parts
-    }
-    return parts
-  }
-
   function patchToolPart(sessionID: string | undefined, messageID: string, part: Part) {
     const sid = sessionID ?? part.sessionID
     if (!sid) return
@@ -1523,6 +1496,7 @@ export const SessionProvider: ParentComponent = (props) => {
       }
 
       for (const msg of messages) {
+        pendingOptimisticParts.delete(msg.id)
         const parts = msg.parts ?? []
         if (mode === "reconcile" && store.parts[msg.id]) {
           // Reconcile on a message already hydrated into the reactive store:
@@ -1583,22 +1557,9 @@ export const SessionProvider: ParentComponent = (props) => {
   function handleMessageCreated(message: Message) {
     if (message.role === "assistant") clearSessionDraftDiscarded(message.sessionID)
     // Message confirmed by server — no longer optimistic.
-    // Clear placeholder parts so they don't duplicate alongside real parts
-    // arriving via individual part.updated events (the server's message.updated
-    // SSE event does NOT include parts).
     const pending = pendingOptimistic.get(message.sessionID)
-    const wasOptimistic = pending?.has(message.id)
     pending?.delete(message.id)
 
-    if (wasOptimistic) {
-      setStore(
-        "parts",
-        produce((p) => {
-          delete p[message.id]
-        }),
-      )
-    }
-
     const exists = (store.messages[message.sessionID] ?? []).some((msg) => msg.id === message.id)
     setStore("messages", message.sessionID, (msgs = []) => {
       // Check if message already exists (optimistic or update case).
@@ -1619,6 +1580,7 @@ export const SessionProvider: ParentComponent = (props) => {
     if (message.parts && message.parts.length > 0) {
       stash.remove(message.id)
       setStore("parts", message.id, message.parts)
+      pendingOptimisticParts.delete(message.id)
     }
     rebuildToolParts(message.sessionID, store.messages[message.sessionID] ?? [])
   }
@@ -1652,6 +1614,8 @@ export const SessionProvider: ParentComponent = (props) => {
       setStore("parts", effectiveMessageID, stashed)
     }
 
+    const optIds = pendingOptimisticParts.get(effectiveMessageID)
+
     setStore(
       "parts",
       produce((parts) => {
@@ -1659,11 +1623,12 @@ export const SessionProvider: ParentComponent = (props) => {
           parts[effectiveMessageID] = []
         }
 
-        const existingIndex = parts[effectiveMessageID].findIndex((p) => p.id === part.id)
+        const list = parts[effectiveMessageID]
+        const existingIndex = list.findIndex((p) => p.id === part.id)
 
         if (existingIndex >= 0) {
           // Update existing part
-          const existing = parts[effectiveMessageID][existingIndex]
+          const existing = list[existingIndex]
           if (
             delta?.type === "text-delta" &&
             delta.textDelta &&
@@ -1680,9 +1645,21 @@ export const SessionProvider: ParentComponent = (props) => {
             }
             Object.assign(existing, part)
           }
+        } else if (optIds && optIds.size > 0) {
+          // Server part arrived for a message with optimistic parts:
+          // replace matching optimistic part in place so the prompt never flickers empty.
+          const optIdx = list.findIndex((p) => optIds.has(p.id) && p.type === part.type)
+          if (optIdx >= 0) {
+            const replaced = list[optIdx]
+            optIds.delete(replaced.id)
+            list[optIdx] = part
+          } else {
+            list.push(part)
+          }
+          if (optIds.size === 0) pendingOptimisticParts.delete(effectiveMessageID)
         } else {
           // Add new part
-          parts[effectiveMessageID].push(part)
+          list.push(part)
         }
       }),
     )
@@ -1861,6 +1838,7 @@ export const SessionProvider: ParentComponent = (props) => {
     if (!message.messageID && sid) aborts.clear(sid)
     if (sid && message.messageID) {
       pendingOptimistic.get(sid)?.delete(message.messageID)
+      pendingOptimisticParts.delete(message.messageID)
       stash.remove(message.messageID)
       batch(() => {
         setStore("messages", sid, (msgs = []) => msgs.filter((m) => m.id !== message.messageID))
@@ -2019,7 +1997,10 @@ export const SessionProvider: ParentComponent = (props) => {
       // Collect message IDs so we can clean up their parts (store + stash)
       const msgs = store.messages[sessionID] ?? []
       const msgIds = msgs.map((m) => m.id)
-      for (const id of msgIds) stash.remove(id)
+      for (const id of msgIds) {
+        stash.remove(id)
+        pendingOptimisticParts.delete(id)
+      }
       clearHiddenErrors(msgIds)
 
       setStore(
@@ -2238,19 +2219,24 @@ export const SessionProvider: ParentComponent = (props) => {
     pendingOptimistic.set(sid, pending)
 
     const parts: Part[] = []
+    const partIds = new Set<string>()
     if (text) {
+      const partId = Identifier.ascending("part")
+      partIds.add(partId)
       parts.push({
         type: "text" as const,
-        id: Identifier.ascending("part"),
+        id: partId,
         messageID,
         text,
         metadata: review ? reviewMetadata(review) : undefined,
       })
     }
     for (const file of files ?? []) {
+      const partId = Identifier.ascending("part")
+      partIds.add(partId)
       parts.push({
         type: "file" as const,
-        id: Identifier.ascending("part"),
+        id: partId,
         messageID,
         mime: file.mime,
         url: file.url,
@@ -2258,6 +2244,7 @@ export const SessionProvider: ParentComponent = (props) => {
         source: file.source,
       })
     }
+    pendingOptimisticParts.set(messageID, partIds)
 
     setStore("messages", sid, (msgs = []) => [...msgs, temp])
     setStore("parts", messageID, parts)
@@ -2862,6 +2849,7 @@ export const SessionProvider: ParentComponent = (props) => {
   function deleteQueuedMessage(sessionID: string, messageID: string) {
     if (!server.isConnected()) return
     pendingOptimistic.get(sessionID)?.delete(messageID)
+    pendingOptimisticParts.delete(messageID)
     finishSubmission(messageID)
     vscode.postMessage({ type: "deleteMessage", sessionID, messageID })
   }
@@ -2915,16 +2903,20 @@ export const SessionProvider: ParentComponent = (props) => {
     return buildCostBreakdown(id, costs, familyLabels(), language.t("context.stats.thisSession"))
   })
 
-  // Status text derived from last assistant message parts
+  // Status text derived from current turn's assistant message parts
   const statusText = createMemo<string | undefined>(() => {
     if (status() === "idle") return undefined
+    const thinking = language.t("ui.sessionTurn.status.thinking")
     const fallback = language.t("ui.sessionTurn.status.consideringNextSteps")
     const id = currentSessionID()
     const msgs = messages()
-    for (let i = msgs.length - 1; i >= 0; i--) {
+    const lastUserIdx = msgs.findLastIndex((m) => m.role === "user")
+    if (lastUserIdx < 0) return thinking
+
+    for (let i = msgs.length - 1; i > lastUserIdx; i--) {
       if (msgs[i].role !== "assistant") continue
       const parts = getParts(msgs[i].id)
-      if (parts.length === 0) break
+      if (parts.length === 0) return thinking
       const raw = computeStatus(parts[parts.length - 1], language.t) ?? fallback
       // When delegating to a subagent and that subagent is blocked on a prompt,
       // replace the generic "Delegating work" label with a more informative one
@@ -2937,7 +2929,7 @@ export const SessionProvider: ParentComponent = (props) => {
       }
       return raw
     }
-    return fallback
+    return thinking
   })
 
   const modelUsage = createMemo<SessionModelUsage | undefined>(() => {