diff --git a/frontend/lib/registry/components/split-panel-layout2/SplitPanelLayout2Component.tsx b/frontend/lib/registry/components/split-panel-layout2/SplitPanelLayout2Component.tsx
index 3bdd2015..6415519e 100644
--- a/frontend/lib/registry/components/split-panel-layout2/SplitPanelLayout2Component.tsx
+++ b/frontend/lib/registry/components/split-panel-layout2/SplitPanelLayout2Component.tsx
@@ -812,11 +812,22 @@ export const SplitPanelLayout2Component: React.FC<SplitPanelLayout2ComponentProp
 
   // 좌측 패널 항목 렌더링
   const renderLeftItem = (item: any, level: number = 0, index: number = 0) => {
-    const idColumn = config.leftPanel?.hierarchyConfig?.idColumn || "id";
+    // ID 컬럼 결정: 설정값 > 데이터에 존재하는 일반적인 ID 컬럼 > 폴백
+    const configIdColumn = config.leftPanel?.hierarchyConfig?.idColumn;
+    const idColumn = configIdColumn || 
+      (item["id"] !== undefined ? "id" : 
+       item["dept_code"] !== undefined ? "dept_code" :
+       item["code"] !== undefined ? "code" : "id");
     const itemId = item[idColumn] ?? `item-${level}-${index}`;
     const hasChildren = item.children?.length > 0;
     const isExpanded = expandedItems.has(String(itemId));
-    const isSelected = selectedLeftItem && selectedLeftItem[idColumn] === item[idColumn];
+    // 선택 상태 확인: 동일한 객체이거나 idColumn 값이 일치해야 함
+    const isSelected = selectedLeftItem && (
+      selectedLeftItem === item ||
+      (item[idColumn] !== undefined && 
+       selectedLeftItem[idColumn] !== undefined &&
+       selectedLeftItem[idColumn] === item[idColumn])
+    );
 
     // displayRow 설정에 따라 컬럼 분류
     const displayColumns = config.leftPanel?.displayColumns || [];