I like that approach, but with the same icons. Why not change the icons color for example?

Great, let´s do that :)

You forgot this one https://phabricator.kde.org/D18591

Ignore the header.php, it's just to work local.

Hi, how could i help here?

I think in Kmail for Plasma 5 the vertical view is default, i remember i had to switch to the split one.

@rjvbb I also prefer that view, but you can change that on menu options right?

Here are some ideas, i think Kontact needs more space for content and less for options.

I also agree to move the left column icons to another place like @ochurlaud suggested, or adding a collapsable column like Opera has now for chat services? I think we need more space for messages.