Especially on modern 16:9 screens, this layout uses the available space way more efficient. But that this is possible with Kmail is not well known and the option to switch to this layout is hidden deep inside the settings. I only learned about it by some blog post, which is probably also not known to many users: https://blogs.churlaud.com/somefoobar/2016/09/17/ive-been-trying-kmail-and/ And even after reading the blog post, I searched quite long for the switch in the KMail settings. Reproducible: Always
it's the same problem for user which doesn't want to use this layout :) If we change default layout other user will have the same problem no ?:)
Sure. ;) I just believe this layout to be objectively better (because of computer screens being more wide than high and therefore using the available space better). In the second place it's of course also a matter of taste, which version you prefer. But it seems natural to prioritize the "objectively better" option and let the user switch to the other one instead of doing it the other way around. But if you don't think one is 'objectively better' than the other, it's also fine and we don't have to argue about it because I don't think changing this is one of the most important things at the moment and I don't have a huge incentive pushing it. This bug/wishlist entry was only meant as a suggestion.