Dear Maintainer,
when opening emails in windows on their own the next email has to opened by
closing the current window, selecting the next one in the folder and opening it
in another window. It would be desirable to be able to navigate through email
from within the email window.
Fun fact, this was an unanswered question on stackexchange 4 years and 9
mtónths ago: https://unix.stackexchange.com/questions/259812/next-unread-
message-shortcut-in-kmail-message-window
This is amplified by kmail's misbehaviour on KDE Wayland. Through the inability
to show the email in the preview pane, emails have to be opened in email
message windows on Wayland (see https://bugs.kde.org/show_bug.cgi?id=414955)