I got a weird problem, and upgrading on 3.14.1 didn't help: When composing a new message and typing the character "h", the claws Help/About window pops up, in the address-line as well as in the text field. That makes that I cannot compose mails no more.
Created attachment 1793 [details] popup window
you have assigned H as a hotkey for the /Help/About menu item. see http://www.claws-mail.org/faq/index.php/Interface#How_can_I_change_the_key-bindings_.28hot-keys.29_in_Claws_Mail.3F