When having view option “Hide checked items” enabled, an empty node (with no children) looks exactly the same as a node with all children hidden.
It happens from time to time, that I accidentally “delete” a seemingly empty node, realizing only later that I deleted valuable (hidden) data. Hidden (checked off) items is basically my “archive”, aka not visible anymore, but still searchable for later reference.
It would be nice if the bullet point on a node with all it’s children hidden looks different than a truly empty node (or some other visual indication). This would help me a lot to stop deleting valuable data 
Visual indication suggestion:
- truly empty node: same as now (simple middle dot)
- node with at least 1 visible child: same as now (middle dot plus solid ring around it)
- node with all children hidden: middle dot plus dashed ring around it