I have encountered two usability problems with EM.
Problem #1 - EMACS keybindings, which typically work in all AppKit Text objects (and which do work in the main compose text object), do not work in the Subject: field. This may be a failure to send events to the superclass, if this is indeed a proper subclass.
Problem #2 - After I click on the “archive” button in the main window, pressing the “delete” key no longer deletes messages. This may be a result of the button panel becoming firstResponder and not properly forwarding the keyboard events.
I am using eMClient 9.2.2041 (570625d)