diff --git a/B06_Section/B06_Section_UI_Section_View.ts b/B06_Section/B06_Section_UI_Section_View.ts
index 78cd7557..5f75c087 100644
--- a/B06_Section/B06_Section_UI_Section_View.ts
+++ b/B06_Section/B06_Section_UI_Section_View.ts
@@ -45,7 +45,10 @@ import {
 } from "./B06_Section_UI_Cross_View_Metrics";
 import { CROSS_HEIGHT } from "./B06_Section_UI_Section_Common";
 import { LONG_PAD } from "./B06_Section_UI_Section_Common";
-import { buildStructureLane } from "../B05_Profile/B05_Profile_UI_Structures_Marks";
+import {
+  buildStructureLane,
+  STRUCTURE_LANE_HEIGHT_PX,
+} from "../B05_Profile/B05_Profile_UI_Structures_Marks";
 import {
   structureAnchorM,
   type StructureInstance,
@@ -491,7 +494,11 @@ export function createSectionView(
     const measured = chartWrap.clientHeight;
     lastChartAvailable =
       measured > 0 ? measured : Math.max(panelHeight() - PANEL_CHROME_PX, MIN_LONG_HEIGHT);
-    const heights = chartHeights(lastChartAvailable);
+    // 알약 레인도 `chartWrap` 안에 서므로 잰 높이에 **이미 들어 있다**. 그 몫을 빼지 않으면
+    // 다음 회차에 잰 값이 그만큼 더 커지고, 그 값으로 그래프를 키우면 또 커지는 되먹임이
+    // 생겨 패널이 16,000px 까지 부푼다(2026-09-07 실측). 빼 두면 한 번에 수렴한다.
+    const laneHeight = markStructures.length && markTypes.length ? STRUCTURE_LANE_HEIGHT_PX : 0;
+    const heights = chartHeights(Math.max(lastChartAvailable - laneHeight, MIN_LONG_HEIGHT));
     const minWidth = longitudinalMinimumWidth(detail.longitudinal, cachedStationInterval);
     const chartWidth = Math.max(renderWidth, minWidth);
     const chart = buildLongitudinalChart({