Vertically scroll previews when they are overflowing.

[HubKing]

For web browsers, when many windows are open, I think the current horizontal scroll is too cumbersome to find a window, because the user has to scroll a lot. How about adding an option to scroll vertically?

That is, instead of

[ 1 2 3 4 5 ] --> [ 2 3 4 5 6 ] --> [ 3 4 5 6 7 ]

this:

[ 1 2 3 4 5 ] --> [ 6 7 8 9 10 ] --> [ 11 12 13 14 15 ]