Yes I agree.. this is critical as clients don't know that scrolling is active if they can't see a scroll indicator.. also scrolling in a prototype chrome is very buggy.

has this been fixed? I am sending to a bunch of clients at the same time and some just have track balls and pads and they can't scroll at all.
Really problematic.

Yes! We've had the exact same problem with clients not realising that the design continued.

I was able to read all the comments on this page. By. (wait for it) Scrolling. Down.
Woah! I know right? Please add scroll bars.

Add a visible scroll bar to the preview page. Right now you have to hover over the design before you are able to scroll. Many clients have complained that they have not been able to scroll bc the way it works isn't obvious to them. Please help. Thanks!

Yes, I just had this problem come up with a client who didn't realize the pages were scrollable.

I use a tablet and without a scrollbar I can't scroll!

When you share a prototype with a client, it isn't immediately obvious that the design is scrollable. I have had a couple of instances of clients not knowing that the designs continue below the fold. An obvious scroll bar added to the prototype view when shared would solve this.

See screenshots mocked up in orange as an example.

Would be very nice have a scroll bar in preview/web mode. This way user could know how much of site left to see and, if he likes, use it too.