Show folder selection in toggled navigation bar (mail)

R: In a toggled navigation bar, make a mail folder selection menu available when a mail account icon is clicked.

E: I like to keep the navigation bar toggled to save space on my laptop. When I want to navigate to a specific mail folder, however, I have to untoggle the navigation bar and then toggle it back in. Would it be possible to make the mail account icons in the navigation bar work such that when I click them, I get a (potentially nested) list of the folders in the account, so I can navigate between them without having to untoggle the navigation bar?

P: nice-to-have enhancement