diff --git a/B06_Section/B06_Section_UI_Cross_Panel_Base.ts b/B06_Section/B06_Section_UI_Cross_Panel_Base.ts
index 017e2716..0d1fe1b6 100644
--- a/B06_Section/B06_Section_UI_Cross_Panel_Base.ts
+++ b/B06_Section/B06_Section_UI_Cross_Panel_Base.ts
@@ -92,7 +92,8 @@ export function bindArrowKeys(
       return;
     }
     const slot = ARROW_SLOT[event.key];
-    if (!slot || root.classList.contains("is-hidden")) return;
+    // 보기가 숨었으면(한 페이지 두 보기 · 계획서 24-3a) 다른 보기의 방향키를 먹지 않는다.
+    if (!slot || root.classList.contains("is-hidden") || !root.getClientRects().length) return;
     const focus = event.target as HTMLElement | null;
     if (focus && (focus.tagName === "SELECT" || focus.tagName === "INPUT")) return;
     for (const container of containers()) {
diff --git a/B06_Section/B06_Section_UI_Cross_Structure_Panel.ts b/B06_Section/B06_Section_UI_Cross_Structure_Panel.ts
index b360e64d..e24f37fa 100644
--- a/B06_Section/B06_Section_UI_Cross_Structure_Panel.ts
+++ b/B06_Section/B06_Section_UI_Cross_Structure_Panel.ts
@@ -457,7 +457,8 @@ export function buildStructurePanel(
       return;
     }
     const slot = ARROW_SLOT[event.key];
-    if (!slot || root.classList.contains("is-hidden")) return;
+    // 보기가 숨었으면(한 페이지 두 보기 · 계획서 24-3a) 다른 보기의 방향키를 먹지 않는다.
+    if (!slot || root.classList.contains("is-hidden") || !root.getClientRects().length) return;
     const focus = event.target as HTMLElement | null;
     if (focus && (focus.tagName === "SELECT" || focus.tagName === "INPUT")) return;
     for (const candidate of [basinRow, moveRow]) {