I wish it were possible, while adding tags to a note, to create a new sub-tag. It is currently quite easy to create a new top-level tag simply by typing its name into the note's "Add tag..." field. What I am suggesting is to choose a delimiter (I know this is a challenge with so large a user base) such that you could type: dog:poodle. This would create a new sub-tag "poodle" under the existing tag "dog," and add the note to "poodle".
Use case for this: In processing new, incoming notes, I often need to create a new sub-tag to fit new subject matter. At present I need to switch over to the