For Other Browser:

FF/IE/Edge: scrollbar can not drag or scroll by wheel
Safari: scrollbar can drag not scroll by wheel

Oh...interesting. Thanks for checking.

Seems we're not the first (even in Chrome) to come across this :) https://lists.w3.org/Archives/Public/www-style/2013Nov/0330.html

In that case, I think we should match other browsers and the thread on www-style and not do anything, in which case I think we can just mark this WontFix?

Could you also see what happens on Android/iOS? We should probably also make sure the behavior is at least consistent - i.e. we should show the scrollbars if we can't use them or scroll with them.

In any case, I think since pointer-events: none *should* affect scrollbars, lets punt on this for now, the finer points of how this should work is lower priority.

I'd actually like to leave this open (sorry, I changed my mind *while* writing my comment above) to track ensuring the behavior is rational. IMO, it's confusing that we show scrollbars that can't be scrolled. 

So just check and make sure we match what Safari overlay scrollbars do. I don't think this is terribly significant but we should hopefully match behavior.

For Safari overlay scrollbar, programmatic scroll will also show the scrollbar. https://jsfiddle.net/xgfgtahw/

Interestingly, it looks like we don't even composite the scroller if it's pointer-events: none, guess we just assume it can't be scrolled by the user so there's no point in promoting it - we get the big scrollbars even with --enable-prefer-compositing-to-lcd text. In anycase, that'll likely get fixed as we move to SPv2 so I think the behavior here is correct for now. Thanks!