벡테스팅 수정

frontend/src/components/VirtualTradingPage.tsx

@@ -58,7 +58,7 @@ import {
 import { pinStrategyEvaluationTimeframes } from '../utils/strategyTimeframePin';
 import { persistVirtualTargetPinned } from '../utils/virtualTargetMutations';
 import {
-  coalesceTargetsToDefaultStrategy,
+  freezeTargetsBeforeGlobalStrategyChange,
   resolveVirtualTargetStrategyId,
 } from '../utils/virtualTargetStrategy';
 import { virtualTargetLimitMessage } from '../utils/virtualTargetLimits';
@@ -165,12 +165,6 @@ const VirtualTradingPage: React.FC<Props> = ({
   useEffect(() => { saveVirtualTargets(targets); }, [targets]);
   useEffect(() => { saveVirtualSession(session); }, [session]);
 
-  /** 예전 데이터: 종목 strategyId에 전역 ID가 복사된 경우 → 기본 전략 따름(null) */
-  useEffect(() => {
-    if (session.globalStrategyId == null) return;
-    setTargets(prev => coalesceTargetsToDefaultStrategy(prev, session.globalStrategyId));
-  }, [session.globalStrategyId]);
-
   useEffect(() => { saveVirtualCardViewMode(viewMode); }, [viewMode]);
   useEffect(() => { saveVirtualGridPreset(gridPreset); }, [gridPreset]);
 
@@ -299,13 +293,11 @@ const VirtualTradingPage: React.FC<Props> = ({
     });
   }, []);
 
+  /** 상단 기본전략 — 신규 추가 종목 템플릿만 변경, 기존 종목 전략은 유지 */
   const handleGlobalStrategyChange = useCallback((strategyId: number | null) => {
-    const next = { ...session, globalStrategyId: strategyId };
-    setSession(next);
-    if (session.running && strategyId) {
-      void syncVirtualTargetsToBackend(targets, next, true);
-    }
-  }, [session, targets]);
+    setTargets(prev => freezeTargetsBeforeGlobalStrategyChange(prev, session.globalStrategyId));
+    setSession(prev => ({ ...prev, globalStrategyId: strategyId }));
+  }, [session.globalStrategyId]);
 
   const handleStart = useCallback(async () => {
     if (targets.length === 0) {