diff --git a/src/components/CandleChart.tsx b/src/components/CandleChart.tsx
index 3f8a07f..c2207d2 100644
--- a/src/components/CandleChart.tsx
+++ b/src/components/CandleChart.tsx
@@ -59,6 +59,9 @@ const PREDEFINED_LABEL_COLORS = [
   '#f97316', // orange
 ];
 
+// === Default Props ===
+const EMPTY_STRING_SET = new Set<string>();
+
 interface DrawingState {
   tool: 'line' | 'rectangle';
   firstPoint: { time: Time; price: number };
@@ -173,7 +176,7 @@ const CandleChart = forwardRef<CandleChartHandle, CandleChartProps>(
     perCandlePredictions = [],
     predictionSpans = [],
     confidenceThreshold = 0.5,
-    selectedLabels = new Set<string>(),
+    selectedLabels = EMPTY_STRING_SET,
     modelInfo = null,
     predictionSummary = null,
     showOnlyDisagreements = false,