Click and drag to horizontal scroll for small screen (Surface) users.
This is a Trello feature that is far more useful than it sounds. You can click and drag the background of any board to scroll through your lists (buckets in Planner) so that you don't have to find a tedious little scroll bar at the bottom of the page. This would also help with Mac support since their browser scrollbars disappear when they aren't being used.
I am surprised by the small amount of votes for this idea. To have to drag a scrollbar to see your other buckets slows workflow right down. Trello's idea of dragging the background is not only brilliant but essential for fast work where you have many buckets. I would also add that when dragging tasks to off-screen buckets should force an auto-scroll. This partially works but is not smooth enough.
I find myself constantly wanting to do this. This seriously is a heavily overlooked feature - it makes navigating the boards so much easier. Never going to be a true Trello replacement without it!
Baronne Mouton commented
Not only for small screen users though... I would say this feature is useful even on the desktop to scroll across