diff --git a/src/blenderbim/blenderbim/bim/module/model/prop.py b/src/blenderbim/blenderbim/bim/module/model/prop.py
index 298270728b..c4dc72b146 100644
--- a/src/blenderbim/blenderbim/bim/module/model/prop.py
+++ b/src/blenderbim/blenderbim/bim/module/model/prop.py
@@ -99,7 +99,10 @@ class BIMModelProperties(PropertyGroup):
         items=[("CLASS", "By Class", ""), ("TYPE", "By Type", ""), ("CUSTOM", "Custom", "")],
         name="Occurrence Name Style",
     )
-    occurrence_name_function: bpy.props.StringProperty(name="Occurrence Name Function")
+    occurrence_name_function: bpy.props.StringProperty(
+        name="Occurrence Name Function",
+        description="Code that will be evaluated to generate occurrence name for CUSTOM occurrence name style",
+    )
     getter_enum = {"ifc_class": get_ifc_class, "relating_type": get_relating_type_id}
     extrusion_depth: bpy.props.FloatProperty(min=0.001, default=42.0, subtype="DISTANCE")
     cardinal_point: bpy.props.EnumProperty(
diff --git a/src/blenderbim/blenderbim/bim/ui.py b/src/blenderbim/blenderbim/bim/ui.py
index a1079f2096..13a0f9e6a6 100644
--- a/src/blenderbim/blenderbim/bim/ui.py
+++ b/src/blenderbim/blenderbim/bim/ui.py
@@ -240,8 +240,9 @@ class BIM_ADDON_preferences(bpy.types.AddonPreferences):
 
         row = layout.row()
         row.prop(context.scene.BIMModelProperties, "occurrence_name_style")
-        row = layout.row()
-        row.prop(context.scene.BIMModelProperties, "occurrence_name_function")
+        if context.scene.BIMModelProperties == "CUSTOM":
+            row = layout.row()
+            row.prop(context.scene.BIMModelProperties, "occurrence_name_function")
 
         row = self.layout.row()
         row.prop(self, "decorations_colour")