Hi,
by activating, are you referring to sleeping tabs that when you hover over them, you wake them up?
in my opinion, I don't think disabling scroll functionality in vertical tabs would be a good thing, because unlike the horizontal tab strip where tabs become smaller and smaller to make room for more tabs, in vertical tab strip, tabs keep their size at all times and don't squeeze together, so it can easily result to some tabs become inaccessible.
