[Users] Keyboard shortcuts

[Neil]

I would like to be able to mark any message as Read or Unread without
opening it.  In Thunderbird I can do this easily. When a message folder
is open any selected message can be marked using the letter m as a
read/unread toggle.

I have searched for something similar in claws, without success. I have
found the Keyboard Shortcuts listing in the Miscellaneous menu from
Preferences but it is not clear how to add your own.

Any help appreciated,

Neil