diff --git a/scripts/microbe_stage/setup.as b/scripts/microbe_stage/setup.as
index 3c600939e33..07497ab9c52 100644
--- a/scripts/microbe_stage/setup.as
+++ b/scripts/microbe_stage/setup.as
@@ -269,6 +269,10 @@ void onReturnFromEditor(CellStageWorld@ world)
 
 }
 
+//
+// TODO: also put these physics callback somewhere more sensible (maybe physics_callbacks.as?)
+//
+
 void cellHitFloatingOrganelle(GameWorld@ world, ObjectID firstEntity, ObjectID secondEntity)
 {
     // Determine which is the organelle