more fixes

app.py

@@ -88,7 +88,11 @@ def _finalize_dataset_load(bundle, state):
     state = {
         "dataframe": df,
         "filtered_df": df,
-        "column_types": bundle.column_types,
+        "column_types": {
+            "numeric": bundle.column_types.numeric,
+            "categorical": bundle.column_types.categorical,
+            "datetime": bundle.column_types.datetime,
+        },
         "filter_meta": filter_metadata(df, bundle.column_types),
         "source_name": bundle.source_name,
     }
@@ -172,11 +176,15 @@ def _populate_column_options(
             empty_dropdown,
         )
 
-    numeric = list(column_types.numeric)
-    categorical = list(column_types.categorical)
-    datetime_cols = list(column_types.datetime)
+    numeric = list(column_types["numeric"])
+    categorical = list(column_types["categorical"])
+    datetime_cols = list(column_types["datetime"])
     all_columns = list(state["dataframe"].columns)
-    defaults = get_default_insight_columns(column_types)
+    
+    defaults = {
+        "numeric": numeric[0] if numeric else None,
+        "datetime": datetime_cols[0] if datetime_cols else None,
+    }
 
     def dropdown(values: Iterable[str], default: Optional[str] = None):
         choices = list(values)