diff --git a/Design:-subflows.md b/Design:-subflows.md
index 541e7c1..3dcc803 100644
--- a/Design:-subflows.md
+++ b/Design:-subflows.md
@@ -20,6 +20,7 @@ A subflow can be used in one of two modes: (this is tbd. Might just stick with s
 * what restrictions should be applied?
     * a single, continuous flow of nodes - aside from comment nodes
     * only one 'left most' node
+* what about subflows with no left most node? Would there be any way to override properties of a contained node? For example, consider a subflow containing an mqtt sub and deserialiser pair where modifying the topic of the mqtt subscriber would be useful.
 
 
 ### Editing a subflow