diff --git a/src/blenderbim/blenderbim/tool/collector.py b/src/blenderbim/blenderbim/tool/collector.py
index 5275ca9954..ed4e9377f5 100644
--- a/src/blenderbim/blenderbim/tool/collector.py
+++ b/src/blenderbim/blenderbim/tool/collector.py
@@ -77,6 +77,9 @@ class Collector(blenderbim.core.tool.Collector):
             blenderbim.core.spatial.assign_container(
                 tool.Ifc, tool.Collector, tool.Spatial, structure_obj=parent_obj, element_obj=obj
             )
+            # NOTE: won't allow assigning IfcElements to the IfcProject directly
+            # and some elements might get missing in other viewers if they're don't support displaying
+            # elements without hierarchy
             blenderbim.core.aggregate.assign_object(
                 tool.Ifc, tool.Aggregate, tool.Collector, relating_obj=parent_obj, related_obj=obj
             )