diff --git a/src/bonsai/bonsai/bim/module/cost/ui.py b/src/bonsai/bonsai/bim/module/cost/ui.py
index 387998e9ac..e8df647071 100644
--- a/src/bonsai/bonsai/bim/module/cost/ui.py
+++ b/src/bonsai/bonsai/bim/module/cost/ui.py
@@ -708,18 +708,16 @@ class BIM_UL_cost_items_trait:
 
 
 class BIM_UL_cost_items(BIM_UL_cost_items_trait, UIList):
-    def __init__(self):
-        self.contract_operator = "bim.contract_cost_item"
-        self.expand_operator = "bim.expand_cost_item"
+    contract_operator = "bim.contract_cost_item"
+    expand_operator = "bim.expand_cost_item"
 
 
 class BIM_UL_cost_item_rates(BIM_UL_cost_items_trait, UIList):
     # A schedule of rates UIList is identical to a regular cost items UIList but
     # we want a separate UIList instance so that you can browse both lists
     # independently in Blender. So we use a trait.
-    def __init__(self):
-        self.contract_operator = "bim.contract_cost_item_rate"
-        self.expand_operator = "bim.expand_cost_item_rate"
+    contract_operator = "bim.contract_cost_item_rate"
+    expand_operator = "bim.expand_cost_item_rate"
 
     def draw_quantity_column(self, layout, cost_item):
         self.draw_uom_column(layout, cost_item)
diff --git a/src/bonsai/bonsai/bim/module/spatial/ui.py b/src/bonsai/bonsai/bim/module/spatial/ui.py
index da20a63d7c..42b5a3cadc 100644
--- a/src/bonsai/bonsai/bim/module/spatial/ui.py
+++ b/src/bonsai/bonsai/bim/module/spatial/ui.py
@@ -264,7 +264,8 @@ class BIM_UL_containers_manager(UIList):
         "IfcRoadPart": "MOD_FLUID",
     }
 
-    def __init__(self):
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
         self.use_filter_show = True
 
     def draw_item(
@@ -338,7 +339,8 @@ class BIM_UL_containers_manager(UIList):
 
 
 class BIM_UL_elements(UIList):
-    def __init__(self):
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
         self.use_filter_show = True
 
     def draw_toggle(self, row: bpy.types.UILayout, is_expanded: bool, index: int):