diff --git a/src/features/agents/Markdown.tsx b/src/features/agents/Markdown.tsx
index a0da3f508..6ba05f6e1 100644
--- a/src/features/agents/Markdown.tsx
+++ b/src/features/agents/Markdown.tsx
@@ -17,7 +17,21 @@ import styles from "./Session.module.css";
 
 const marked = new Marked({ gfm: true, breaks: true });
 
+/** Rendered messages by text, least recently used first: reopening a conversation renders it again. */
+const rendered = new Map<string, string>();
+const RENDERED_MAX = 500;
+
 export function markdownHtml(text: string): string {
+  let html = rendered.get(text);
+  if (html === undefined) {
+    html = renderHtml(text);
+    if (rendered.size >= RENDERED_MAX) rendered.delete(rendered.keys().next().value!);
+  } else rendered.delete(text);
+  rendered.set(text, html);
+  return html;
+}
+
+function renderHtml(text: string): string {
   const html = marked.parse(text, { async: false }) as string;
   // Replies can quote repository content. Styles would reach the whole IDE, and the click
   // handlers below trust `data-copy` / `data-path`, which only `enhance` may set.
diff --git a/src/features/agents/SessionEditor.tsx b/src/features/agents/SessionEditor.tsx
index b74a2b4cc..02f91fa1d 100644
--- a/src/features/agents/SessionEditor.tsx
+++ b/src/features/agents/SessionEditor.tsx
@@ -1,5 +1,14 @@
 /** An agent task as an editor tab: the conversation, a composer and the task's changed files. */
-import { Fragment, useEffect, useLayoutEffect, useMemo, useRef, useState, type RefObject } from "react";
+import {
+  Fragment,
+  startTransition,
+  useEffect,
+  useLayoutEffect,
+  useMemo,
+  useRef,
+  useState,
+  type RefObject,
+} from "react";
 import clsx from "clsx";
 import { useShallow } from "zustand/react/shallow";
 import type { AgentChange, AgentEntry, AgentImage, AgentLimit, AgentRetry, AgentTask, AgentUsage } from "@/bindings";
@@ -92,14 +101,17 @@ function TaskSession({ id, docked }: { id: string; docked: boolean }) {
     useShallow((s) => path.map((sub, i) => findSubagent(s.entries.get(entriesKey(id, path[i - 1] ?? null)), sub))),
   );
   useEffect(() => {
-    void loadEntries(id).catch(() => undefined);
+    // Loaded entries are kept current by the task's events: reopening the tab needn't fetch them again.
+    if (!useAgents.getState().entries.has(id)) void loadEntries(id).catch(() => undefined);
     void refreshChanges(id);
   }, [id]);
   useEffect(() => {
     if (!docked || !changesOpen) return markVisible(id);
   }, [id, docked, changesOpen]);
   useEffect(() => {
-    if (view) void loadEntries(id, view).catch(() => undefined);
+    if (view && !useAgents.getState().entries.has(entriesKey(id, view))) {
+      void loadEntries(id, view).catch(() => undefined);
+    }
   }, [id, view]);
   const openSubagent = (sub: string) => setPath((p) => [...p, sub]);
   const [finding, setFinding] = useState(false);
@@ -412,6 +424,9 @@ interface StreamProps {
   onCloseFind: () => void;
 }
 
+/** Entries rendered at a time when a conversation opens at its end. */
+const ENTRY_BATCH = 40;
+
 function Stream({ task, entries, subagent, onOpenSubagent, finding, findFocus, onCloseFind }: StreamProps) {
   const ref = useRef<HTMLDivElement>(null);
   useSelectionBoundary(ref);
@@ -419,6 +434,13 @@ function Stream({ task, entries, subagent, onOpenSubagent, finding, findFocus, o
   const positions = useAgents.getState().scrollPositions;
   const position = useRef(positions.get(key) ?? { top: 0, stick: true });
   const restored = useRef(false);
+  // Opened at the end, the last entries come first and the earlier ones follow in batches:
+  // reopening a long conversation paints at once. A kept offset needs them all.
+  const [shown, setShown] = useState(() => (positions.get(key)?.stick === false ? Infinity : ENTRY_BATCH));
+  const start = finding || !entries ? 0 : Math.max(0, entries.length - shown);
+  useEffect(() => {
+    if (start > 0) startTransition(() => setShown((n) => n + ENTRY_BATCH));
+  }, [start]);
   useLayoutEffect(() => {
     const el = ref.current;
     if (!el || entries === null) return;
@@ -470,16 +492,18 @@ function Stream({ task, entries, subagent, onOpenSubagent, finding, findFocus, o
         {entries === null ? (
           <Spinner />
         ) : (
-          entries.map((entry, i) => (
-            <Entry
-              key={i}
-              task={task}
-              entry={entry}
-              turn={turns?.get(i) ?? null}
-              turnCount={turns?.size ?? 0}
-              onOpenSubagent={onOpenSubagent}
-            />
-          ))
+          entries
+            .slice(start)
+            .map((entry, i) => (
+              <Entry
+                key={start + i}
+                task={task}
+                entry={entry}
+                turn={turns?.get(start + i) ?? null}
+                turnCount={turns?.size ?? 0}
+                onOpenSubagent={onOpenSubagent}
+              />
+            ))
         )}
         {subagent && subagentWorking(subagent.status) && (
           <div className={styles.working}>
diff --git a/src/features/agents/sessionState.test.tsx b/src/features/agents/sessionState.test.tsx
index 9d0a361f4..4a8261400 100644
--- a/src/features/agents/sessionState.test.tsx
+++ b/src/features/agents/sessionState.test.tsx
@@ -14,14 +14,16 @@ const backend = vi.hoisted(() => ({
   entries: new Map<string, AgentEntry[]>(),
   changes: [] as AgentChange[],
   answers: [] as Array<[string, number, string | null]>,
+  fetched: [] as string[],
 }));
 vi.mock("@/platform/ipc", async (original) => ({
   ...(await original<typeof import("@/platform/ipc")>()),
   commands: {
-    agentEntries: async (id: string, sub: string | null) => ({
-      status: "ok",
-      data: backend.entries.get(sub ? `${id}/${sub}` : id) ?? [],
-    }),
+    agentEntries: async (id: string, sub: string | null) => {
+      const key = sub ? `${id}/${sub}` : id;
+      backend.fetched.push(key);
+      return { status: "ok", data: backend.entries.get(key) ?? [] };
+    },
     agentChanges: async () => ({ status: "ok", data: backend.changes }),
     vcsBranchInfo: async () => ({ status: "ok", data: { head: "main" } }),
     agentRespond: async (task: string, permission: number, option: string | null) => {
@@ -177,6 +179,29 @@ describe("a pending permission request in the conversation", () => {
 });
 
 describe("session state across tasks and hosts", () => {
+  it("fetches a conversation once and shows it again from the store when its tab reopens", async () => {
+    const entries = new Map(useAgents.getState().entries);
+    entries.delete("A");
+    useAgents.setState({ entries });
+    backend.fetched = [];
+    const first = render(<SessionEditor input={input("A")} />);
+    expect(await screen.findByText("Answer A")).toBeInTheDocument();
+    first.unmount();
+    render(<SessionEditor input={input("A")} />);
+    expect(screen.getByText("Answer A")).toBeInTheDocument();
+    await act(async () => {});
+    expect(backend.fetched).toEqual(["A"]);
+  });
+
+  it("opens a long conversation at its end and renders the earlier entries after it", async () => {
+    const entries = Array.from({ length: 150 }, (_, i): AgentEntry => ({ type: "agent", text: `Reply ${i}` }));
+    useAgents.setState({ entries: new Map(useAgents.getState().entries).set("A", entries) });
+    render(<SessionEditor input={input("A")} />);
+    expect(screen.getByText("Reply 149")).toBeInTheDocument();
+    expect(await screen.findByText("Reply 0")).toBeInTheDocument();
+    expect(stream().children).toHaveLength(150);
+  });
+
   it("returns to the task conversation when the docked task changes after opening a subagent", async () => {
     const dispose = registerActions(taskActions);
     try {
diff --git a/src/features/vcs/GitLog.tsx b/src/features/vcs/GitLog.tsx
index 89edb7bb5..51bcb64ac 100644
--- a/src/features/vcs/GitLog.tsx
+++ b/src/features/vcs/GitLog.tsx
@@ -1091,6 +1091,8 @@ export function viewOptionsMenu(o: LogOptions): MenuItem[] {
         toggle("Date", o, "showDate"),
         toggle("Hash", o, "showHash"),
         toggle("Signature", o, "showSignature"),
+        { kind: "separator" },
+        toggle("Column Headers", o, "showColumnHeaders"),
       ],
     },
     { kind: "separator" },
@@ -1604,15 +1606,17 @@ function CommitList() {
           );
         }}
       >
-        <div className={clsx(styles.row, styles.columnHeader)} style={{ minWidth }}>
-          {opts.showRepository && useVcs.getState().roots.length > 1 && (
-            <span className={styles.colRepository}>{tx("Repository")}</span>
-          )}
-          <span className={styles.colSubject}>{tx("Commit")}</span>
-          {columns.map((column) => (
-            <LogColumnHeader key={column.id} column={column} columns={columns} options={opts} />
-          ))}
-        </div>
+        {opts.showColumnHeaders && (
+          <div className={clsx(styles.row, styles.columnHeader)} style={{ minWidth }}>
+            {opts.showRepository && useVcs.getState().roots.length > 1 && (
+              <span className={styles.colRepository}>{tx("Repository")}</span>
+            )}
+            <span className={styles.colSubject}>{tx("Commit")}</span>
+            {columns.map((column) => (
+              <LogColumnHeader key={column.id} column={column} columns={columns} options={opts} />
+            ))}
+          </div>
+        )}
         {!commits.length && !loading && finished && (
           <div className={styles.message}>{headCommit ? tx("No commits match the filters") : tx("No commits yet")}</div>
         )}
diff --git a/src/features/vcs/__tests__/graph.test.ts b/src/features/vcs/__tests__/graph.test.ts
index 97464ef7e..5b575aa50 100644
--- a/src/features/vcs/__tests__/graph.test.ts
+++ b/src/features/vcs/__tests__/graph.test.ts
@@ -1,5 +1,5 @@
 import { describe, expect, it } from "vitest";
-import { computeGraph, straightenLaneChanges } from "../graph";
+import { compactLanes, computeGraph, straightenLaneChanges, type GraphRow } from "../graph";
 
 const c = (id: string, ...parents: string[]) => ({ id, parents });
 
@@ -106,3 +106,61 @@ describe("straightenLaneChanges", () => {
     expect(rows[2]!.up[0]!.fromX).toBeUndefined();
   });
 });
+
+describe("compactLanes", () => {
+  const row = (lane: number, up: [number, number][], down: [number, number][], width = 9): GraphRow => ({
+    lane,
+    color: 0,
+    up: up.map(([from, to]) => ({ from, to, color: 0 })),
+    down: down.map(([from, to]) => ({ from, to, color: 0 })),
+    width,
+  });
+
+  it("packs the lanes of each row side by side, in their order", () => {
+    // Lanes 2 and 7 (branch layout leaves the slots between them empty); 7 merges into 2.
+    const rows = compactLanes([
+      row(
+        7,
+        [],
+        [
+          [2, 2],
+          [7, 7],
+        ],
+      ),
+      row(
+        2,
+        [
+          [2, 2],
+          [7, 2],
+        ],
+        [[2, 2]],
+      ),
+      row(2, [[2, 2]], []),
+    ]);
+    expect(rows.map((r) => r.lane)).toEqual([1, 0, 0]);
+    expect(rows.map((r) => r.width)).toEqual([2, 2, 1]);
+    expect(rows[0]!.down.map((s) => [s.from, s.to])).toEqual([
+      [0, 0],
+      [1, 1],
+    ]);
+    expect(rows[1]!.up.map((s) => [s.from, s.to])).toEqual([
+      [0, 0],
+      [1, 0],
+    ]);
+  });
+
+  it("keeps lines joined across rows when a lane is freed in between", () => {
+    const laid = computeGraph([
+      { id: "a", parents: ["c"], refs: ["a"] },
+      { id: "b", parents: ["c"], refs: ["b"] },
+      { id: "x", parents: ["c"], refs: ["x"] },
+      { id: "c", parents: [], refs: ["main"] },
+    ]).rows;
+    const rows = compactLanes(laid);
+    for (let r = 0; r + 1 < rows.length; r++) {
+      const below = new Set(rows[r]!.down.map((s) => s.to));
+      expect(new Set(rows[r + 1]!.up.map((s) => s.from))).toEqual(below);
+      expect(Math.max(...below)).toBe(below.size - 1);
+    }
+  });
+});
diff --git a/src/features/vcs/__tests__/logUiFeatures.test.tsx b/src/features/vcs/__tests__/logUiFeatures.test.tsx
index 2159cf57b..378055ff1 100644
--- a/src/features/vcs/__tests__/logUiFeatures.test.tsx
+++ b/src/features/vcs/__tests__/logUiFeatures.test.tsx
@@ -149,7 +149,14 @@ describe("log controls", () => {
     expect(screen.getByRole("status")).toHaveTextContent("b");
   });
 
+  it("hides the column headers unless View Options shows them", async () => {
+    render(<LogView />);
+    await screen.findByRole("listbox", { name: "Commits" });
+    expect(screen.queryByRole("separator", { name: "Resize Author column" })).toBeNull();
+  });
+
   it("resizes and reorders columns using the keyboard", async () => {
+    useLogOptions.setState({ showColumnHeaders: true });
     render(<LogView />);
     const author = await screen.findByRole("separator", { name: "Resize Author column" });
     fireEvent.keyDown(author, { key: "ArrowRight" });
diff --git a/src/features/vcs/graph.ts b/src/features/vcs/graph.ts
index 1f160952f..b6e84dd53 100644
--- a/src/features/vcs/graph.ts
+++ b/src/features/vcs/graph.ts
@@ -506,6 +506,30 @@ export function hideLongEdges(rows: readonly GraphRow[], minLength = LONG_EDGE):
   return out;
 }
 
+/**
+ * Packs each row's lanes side by side, in their order: lanes laid out by branch leave
+ * gaps (one per branch) and hidden long edges free theirs. Each row boundary and each
+ * node level is packed on its own; adjacent rows share the boundary, so lines stay joined.
+ */
+export function compactLanes(rows: readonly GraphRow[]): GraphRow[] {
+  const ranks = (lanes: Iterable<number>) => new Map([...new Set(lanes)].sort((a, b) => a - b).map((l, i) => [l, i]));
+  const boundaries = Array.from({ length: rows.length + 1 }, (_, r) =>
+    ranks([...(rows[r]?.up.map((s) => s.from) ?? []), ...(rows[r - 1]?.down.map((s) => s.to) ?? [])]),
+  );
+  return rows.map((row, r) => {
+    const node = ranks([row.lane, ...row.up.map((s) => s.to), ...row.down.map((s) => s.from)]);
+    const top = boundaries[r]!;
+    const bottom = boundaries[r + 1]!;
+    return {
+      ...row,
+      lane: node.get(row.lane)!,
+      up: row.up.map((s) => ({ ...s, from: top.get(s.from)!, to: node.get(s.to)! })),
+      down: row.down.map((s) => ({ ...s, from: node.get(s.from)!, to: bottom.get(s.to)! })),
+      width: Math.max(node.size, top.size, bottom.size),
+    };
+  });
+}
+
 /**
  * Draws a lane change as one straight diagonal across the row boundary, like IDEA: a half-row
  * segment that changes lane and the vertical half of the neighbouring row that continues it meet
diff --git a/src/features/vcs/logOptions.ts b/src/features/vcs/logOptions.ts
index 4e594a831..835b4a096 100644
--- a/src/features/vcs/logOptions.ts
+++ b/src/features/vcs/logOptions.ts
@@ -22,6 +22,8 @@ export interface LogOptions {
   showDate: boolean;
   showHash: boolean;
   showSignature: boolean;
+  /** The row naming the columns, where they are resized and reordered. */
+  showColumnHeaders: boolean;
   highlightMine: boolean;
   highlightMerges: boolean;
   highlightCurrentBranch: boolean;
@@ -56,6 +58,7 @@ export const DEFAULT_LOG_OPTIONS: LogOptions = {
   showDate: true,
   showHash: false,
   showSignature: false,
+  showColumnHeaders: false,
   highlightMine: true,
   highlightMerges: true,
   highlightCurrentBranch: true,
diff --git a/src/features/vcs/logPresentation.ts b/src/features/vcs/logPresentation.ts
index c4471c990..77500a369 100644
--- a/src/features/vcs/logPresentation.ts
+++ b/src/features/vcs/logPresentation.ts
@@ -1,4 +1,11 @@
-import { collapseLinear, computeGraph, hideLongEdges, linearizeMerges, straightenLaneChanges } from "./graph";
+import {
+  collapseLinear,
+  compactLanes,
+  computeGraph,
+  hideLongEdges,
+  linearizeMerges,
+  straightenLaneChanges,
+} from "./graph";
 import { commitKey, graphCommit, type RepoCommit } from "./multiRoot";
 import type { LogOptions } from "./logOptions";
 
@@ -26,6 +33,6 @@ export function presentLogGraph(
   const byId = new Map(all.map((c) => [commitKey(c), c]));
   const commits = graph.map((c) => byId.get(c.id)!);
   const laid = computeGraph(graph).rows;
-  const rows = straightenLaneChanges(options.longEdges ? laid : hideLongEdges(laid));
+  const rows = straightenLaneChanges(compactLanes(options.longEdges ? laid : hideLongEdges(laid)));
   return { commits, graph, rows, linear, collapsed };
 }
diff --git a/src/platform/locales/text/zh.json b/src/platform/locales/text/zh.json
index 32cf99260..1de8973f8 100644
--- a/src/platform/locales/text/zh.json
+++ b/src/platform/locales/text/zh.json
@@ -473,6 +473,7 @@
   "Color scheme preview": "配色方案预览",
   "Color theme": "颜色主题",
   "Column": "列",
+  "Column Headers": "列标题",
   "Column Selection Mode": "列选择模式",
   "Columns": "列",
   "Comma-separated column numbers, e.g. 80, 100.": "逗号分隔的列号，例如 80, 100。",