hi, Currently Thunderbird supports vertical layout. But the problem with it the thread has columns which takes quite some space. There is one more efficient vertical laoyout nowdays used in many email clients (e.g. Geary). (See screenshot attached). Sort of a "stacked vertical" where each thread stacks the info (subject, from, date, etc) within the thread without columns quite nicely which saves lots of space for the message pane. Does anybody know if there's an add-on for this ? (I've searched it but couldn't find in the store) Or otherwise maybe somebody can guide my how to develop such a layout myself ? Thanks