diff --git a/B07_DesignDetail/B07_DesignDetail_Engine_Cad_Cover.py b/B07_DesignDetail/B07_DesignDetail_Engine_Cad_Cover.py
index 28d58b7f..76fe67cb 100644
--- a/B07_DesignDetail/B07_DesignDetail_Engine_Cad_Cover.py
+++ b/B07_DesignDetail/B07_DesignDetail_Engine_Cad_Cover.py
@@ -30,6 +30,9 @@ from B07_DesignDetail.B07_DesignDetail_Engine_Template import (
 )
 
 COVER_TEMPLATE = "00_template_cover"
+# 표지는 엔티티가 전부 도각(잠금)이라 그대로 두면 덧그릴 자리가 없다 — 잠금 아닌
+# 도면층을 하나 실어 사용자가 적을 자리를 준다(2026-09-01).
+NOTE_LAYER_ID = "b08-cover-note"
 
 
 def build_cover_drawing(drawing_id: str, fields: dict[str, str] | None = None) -> dict[str, Any]:
@@ -52,5 +55,8 @@ def build_cover_drawing(drawing_id: str, fields: dict[str, str] | None = None) -
     return {
         "format": DRAWING_FORMAT,
         "entities": entities,
-        "layers": [_layer(FRAME_LAYER_ID, "도각", locked=True)],
+        "layers": [
+            _layer(NOTE_LAYER_ID, "주기"),
+            _layer(FRAME_LAYER_ID, "도각", locked=True),
+        ],
     }
diff --git a/B07_DesignDetail/openwebcad/src/components/RibbonWidgets.tsx b/B07_DesignDetail/openwebcad/src/components/RibbonWidgets.tsx
index fe8ece4a..5e303d01 100644
--- a/B07_DesignDetail/openwebcad/src/components/RibbonWidgets.tsx
+++ b/B07_DesignDetail/openwebcad/src/components/RibbonWidgets.tsx
@@ -117,11 +117,15 @@ export const LayersWidget: FC = () => {
 			<label className="cad-prop cad-prop--wide" title="현재 도면층">
 				<span>현재 도면층</span>
 				<select value={activeLayerId} onChange={(event) => setActiveLayerId(event.target.value)}>
-					{layers.map((layer) => (
-						<option key={layer.id} value={layer.id}>
-							{layer.name}
-						</option>
-					))}
+					{/* 잠금 도면층(배경)은 고를 수 없으니 보여 주지 않는다. 현재 층이 잠금이면
+					    (전부 잠금인 도면) 표시가 비지 않게 그 항목만 남긴다. */}
+					{layers
+						.filter((layer) => !layer.isLocked || layer.id === activeLayerId)
+						.map((layer) => (
+							<option key={layer.id} value={layer.id}>
+								{layer.name}
+							</option>
+						))}
 				</select>
 			</label>
 			<button
diff --git a/B07_DesignDetail/openwebcad/src/helpers/autosave.ts b/B07_DesignDetail/openwebcad/src/helpers/autosave.ts
index 05e6133c..0475c919 100644
--- a/B07_DesignDetail/openwebcad/src/helpers/autosave.ts
+++ b/B07_DesignDetail/openwebcad/src/helpers/autosave.ts
@@ -6,7 +6,7 @@
 import { toast } from 'react-toastify';
 import { HtmlEvent } from '../App.types';
 import type { Entity } from '../entities/Entity';
-import { getEntities, setActiveLayerId, setEntities, setLayers } from '../state';
+import { getEntities, resetUndoBaseline, setActiveLayerId, setEntities, setLayers } from '../state';
 import { exportEntitiesAndLayersToJsonString } from './import-export-handlers/export-entities-to-json';
 import { getEntitiesAndLayersFromJsonString } from './import-export-handlers/import-entities-from-json';
 
@@ -64,6 +64,7 @@ export async function restoreRecovery(): Promise<void> {
 	setEntities(drawing.entities, true);
 	setLayers(drawing.layers);
 	setActiveLayerId(drawing.layers[0].id);
+	resetUndoBaseline();
 	toast.success(`백업을 되살렸습니다 (${new Date(file.savedAt).toLocaleString()}).`);
 }
 
diff --git a/B07_DesignDetail/openwebcad/src/helpers/debug-hook.ts b/B07_DesignDetail/openwebcad/src/helpers/debug-hook.ts
index e3d4a835..32bd16c2 100644
--- a/B07_DesignDetail/openwebcad/src/helpers/debug-hook.ts
+++ b/B07_DesignDetail/openwebcad/src/helpers/debug-hook.ts
@@ -2,7 +2,7 @@
  * 화면 검증용 상태 조회 창구 — 브라우저 콘솔·자동화 스크립트가
  * window.__aisloCad로 현재 객체·도면층·선택을 읽는다. 앱 동작에는 관여하지 않는다.
  */
-import { getEntities, getLayers, getSelectedEntityIds } from '../state';
+import { getEntities, getLayers, getSelectedEntityIds, getSnapPoint } from '../state';
 import { isEntityHidden } from './visibility';
 
 export function registerCadDebugHook(): void {
@@ -28,5 +28,7 @@ export function registerCadDebugHook(): void {
 			}),
 		layers: () => getLayers(),
 		selection: () => getSelectedEntityIds(),
+		// 마우스 위치의 객체 스냅점 — 잠금 도면층(도각)이 스냅에 끼는지 검증할 때 읽는다.
+		snap: () => getSnapPoint(),
 	};
 }
diff --git a/B07_DesignDetail/openwebcad/src/integration/aislo-drawing-bridge.ts b/B07_DesignDetail/openwebcad/src/integration/aislo-drawing-bridge.ts
index 32477ae5..272aa8b5 100644
--- a/B07_DesignDetail/openwebcad/src/integration/aislo-drawing-bridge.ts
+++ b/B07_DesignDetail/openwebcad/src/integration/aislo-drawing-bridge.ts
@@ -10,6 +10,7 @@ import {
 	getEntities,
 	getLayers,
 	getScreenCanvasDrawController,
+	resetUndoBaseline,
 	setActiveLayerId,
 	setDesignMeta,
 	setEntities,
@@ -123,6 +124,8 @@ export function registerAisloDrawingBridge() {
 			setEntities(drawing.entities, false);
 			setLayers(drawing.layers);
 			setActiveLayerId(drawing.layers[0].id);
+			// 실은 도면이 되돌리기의 바닥 — 첫 Ctrl+Z가 백지로 가지 않게 한다.
+			resetUndoBaseline();
 			// 설계 컨텍스트(제목·측점정보·확정상태·수량표)를 수량 패널에 반영
 			setDesignMeta(event.data.meta ?? null);
 			getScreenCanvasDrawController().zoomToFitScreen();
diff --git a/B07_DesignDetail/openwebcad/src/state.test.ts b/B07_DesignDetail/openwebcad/src/state.test.ts
new file mode 100644
index 00000000..08caaf08
--- /dev/null
+++ b/B07_DesignDetail/openwebcad/src/state.test.ts
@@ -0,0 +1,48 @@
+import { beforeAll, describe, expect, it } from 'vitest';
+import type { Entity } from './entities/Entity';
+import {
+	getActiveLayerId,
+	getEntities,
+	resetUndoBaseline,
+	setActiveLayerId,
+	setEntities,
+	setLayers,
+	undo,
+} from './state';
+
+const layer = (id: string, isLocked: boolean) => ({
+	id,
+	name: id,
+	isVisible: true,
+	isLocked,
+});
+
+describe('setActiveLayerId', () => {
+	it('잠금 도면층(배경)은 현재 도면층이 되지 않고 잠금 아닌 첫 층으로 간다', () => {
+		setLayers([layer('도각', true), layer('계획선', false)]);
+		setActiveLayerId('도각');
+		expect(getActiveLayerId()).toBe('계획선');
+	});
+
+	it('잠금 아닌 층이 하나도 없으면 요청값을 그대로 둔다', () => {
+		setLayers([layer('도각', true)]);
+		setActiveLayerId('도각');
+		expect(getActiveLayerId()).toBe('도각');
+	});
+});
+
+describe('resetUndoBaseline', () => {
+	// 상태 변경 알림만 window로 나간다 — 노드 환경이라 받는 시늉만 시킨다.
+	beforeAll(() => {
+		(globalThis as { window?: unknown }).window = { dispatchEvent: () => true };
+	});
+
+	it('기준선을 세운 뒤의 되돌리기는 실은 도면까지만 물러난다', () => {
+		const loaded = [{ id: 'a' } as unknown as Entity];
+		setEntities(loaded, false);
+		resetUndoBaseline();
+		setEntities([...loaded, { id: 'b' } as unknown as Entity], true);
+		undo();
+		expect(getEntities()).toHaveLength(1);
+	});
+});
diff --git a/B07_DesignDetail/openwebcad/src/state.ts b/B07_DesignDetail/openwebcad/src/state.ts
index b91124b1..a37414b4 100644
--- a/B07_DesignDetail/openwebcad/src/state.ts
+++ b/B07_DesignDetail/openwebcad/src/state.ts
@@ -415,6 +415,12 @@ export const setLayers = (newLayers: Layer[], triggerReact = true) => {
 	}
 };
 export const setActiveLayerId = (newActiveLayerId: string, triggerReact = true) => {
+	// 잠금 도면층(도각·원지반 등 배경)은 현재 도면층이 될 수 없다 — 새 객체가 배경으로
+	// 떨어지면 그린 즉시 집지도 지우지도 못한다. 호출부(브리지·복구·가져오기·도면층
+	// 패널·리본)마다 거르지 않고 여기 한 곳에서 잠금 아닌 첫 층으로 돌린다.
+	if (layersById.get(newActiveLayerId)?.isLocked) {
+		newActiveLayerId = layers.find((layer) => !layer.isLocked)?.id ?? newActiveLayerId;
+	}
 	activeLayerId = newActiveLayerId;
 
 	if (triggerReact) {
@@ -510,6 +516,15 @@ function updateStates(undoState: UndoState) {
 	}
 }
 
+/**
+ * 지금 객체 목록을 되돌리기 스택의 바닥으로 삼는다. 서버 도면을 실은 직후에 부른다 —
+ * 안 부르면 첫 Ctrl+Z가 도면을 싣기 전의 빈 상태로 되돌아가 화면이 백지가 된다.
+ */
+export function resetUndoBaseline() {
+	undoStack.clear(StateVariable.entities);
+	undoStack.push({ variable: StateVariable.entities, value: entities });
+}
+
 export function undo() {
 	const undoState = undoStack.undo();
 	if (!undoState) return;