I have discovered a bug with toolbars in vertical (left/right/center) in dualmode.
If you have a toolbar between the listers and then you add another toolbar under the first one that is wider, the first one is first drawn up and then it changes so that it is redrawn to a new width every time you switch between the lists. And it only occurs when it's a menu button.
Maybe not a high-priority bug, but a small bug 
Hard to get on a Gif anim but you see the bug a few times. Happens every time not just sometimes
Edit: Can add that it happens every time the list is updated. F5 or change folder