[RCD] Widescreen layout (three column view) is coming to you

[A.L.E.C]

I just pushed "layout modes" change into dev-layouts branch. This is an
implementation of three column view for mail UI.

This is a BC breaking change. So, if you're an author of a skin or a
plugin that modifies the messages list, you'll most likely have to do
some modifications of your code.

You can also just start beta-testing of this change, so it will be ready
for 1.3-beta release. Have fun!

https://kolabian.wordpress.com/2016/09/17/widescreen-layout-aka-three-column-view/