Move/Copy/Transfer/Clone to absolutely needs a tree structure

I am very upset as I am not able to use Airmail simply because there is no tree structure (with folder opening in sequence) in the "Move/Copy/Transfer/Clone to" actions.
I have very many folders and without a way to navigate through my tree of folders opening them with a certain order it is simply impossible to me to use Airmail.
Now all of them appear in a very very very long vertical list just indented.
Thunderbird has such structure for those actions and this simple feature makes Thunderbird much simpler to be used.
Please copy such a feature if you want people really use Airmail.

adolfo.avella about Airmail - Lightning Fast Email, v3.0