diff --git a/frontend/src/components/calendar/CalendarPage.tsx b/frontend/src/components/calendar/CalendarPage.tsx
index dc58d13..dff063a 100644
--- a/frontend/src/components/calendar/CalendarPage.tsx
+++ b/frontend/src/components/calendar/CalendarPage.tsx
@@ -187,12 +187,13 @@ export default function CalendarPage() {
     return () => cancelAnimationFrame(rafId);
   }, [panelOpen]);
 
-  // Scroll wheel navigation in month view
+  // Scroll wheel navigation in month view (disabled when detail panel is open)
   useEffect(() => {
     const el = calendarContainerRef.current;
     if (!el) return;
     let debounceTimer: ReturnType<typeof setTimeout> | null = null;
     const handleWheel = (e: WheelEvent) => {
+      if (panelOpen) return;
       // Skip wheel navigation on touch devices (let them scroll normally)
       if ('ontouchstart' in window) return;
       const api = calendarRef.current?.getApi();
@@ -207,7 +208,7 @@ export default function CalendarPage() {
     };
     el.addEventListener('wheel', handleWheel, { passive: false });
     return () => el.removeEventListener('wheel', handleWheel);
-  }, []);
+  }, [panelOpen]);
 
   // AW-2: Track visible date range for scoped event fetching
   // W-02 fix: Initialize from current month to avoid unscoped first fetch