diff --git a/MyTimeline.py b/MyTimeline.py
index 8b72e9a..f980871 100644
--- a/MyTimeline.py
+++ b/MyTimeline.py
@@ -473,7 +473,7 @@ class MyTimelineView(NavigationView):
         self._cached_min_date: Optional[int] = None
         self._cached_max_date: Optional[int] = None
         self._event_to_person_cache: Dict[str, Optional['Person']] = {}  # Event handle -> Person object (or None)
-        self._event_type_normalization_cache: Dict[EventType, int] = {}  # Cache for event type normalization
+        self._event_type_normalization_cache: Dict[int, int] = {}  # Cache for event type normalization (key: hash/id, value: normalized int)
         self._normalized_active_event_types: Optional[Set[int]] = None  # Pre-computed normalized active types
         
         # Filter state
@@ -2064,10 +2064,7 @@ class MyTimelineView(NavigationView):
         Returns:
             int: The integer value of the event type.
         """
-        # Check cache first
-        if event_type in self._event_type_normalization_cache:
-            return self._event_type_normalization_cache[event_type]
-        
+        # Normalize to integer first (fast operation)
         try:
             if isinstance(event_type, int):
                 normalized = event_type
@@ -2078,8 +2075,12 @@ class MyTimelineView(NavigationView):
         except (TypeError, ValueError, AttributeError):
             normalized = 0  # Default to 0 if conversion fails
         
-        # Cache the result
-        self._event_type_normalization_cache[event_type] = normalized
+        # Use normalized value as cache key (ensures same values share same key)
+        # Check cache - if we've seen this normalized value before, we already know it
+        # This cache is mainly useful for avoiding repeated int() calls on same objects
+        if normalized not in self._event_type_normalization_cache:
+            self._event_type_normalization_cache[normalized] = normalized
+        
         return normalized
     
     def _is_event_type_enabled(self, event_type: EventType) -> bool: