As I prefer to manually mark my email as read, I turned of the automatic marking.
But how are you suppose to mark message as read? In KMail I have an "Mark as read"-button in my tool-bar.
In claws I couldn't find it when editing my tool-bar, and it doesn't have a key-binding, mark as unread have one, but not mark as read??
Shortest path i found so far is: menu->m->e, but thats 3 clicks
You can choose and set your own keybinding:
http://www.claws-mail.org/faq/index.php/Interface#How_can_I_change_the_key-bindings_.28hot-keys.29_in_Claws_Mail.3F
Right click on the message > mark > mark as read. That is 2 clicks.