Don't forget the near religious debate that is scrollbar snapback: skim a document backwards to review an earlier point, or forwards to determine if it's worth further time investment, and then release the mouse button outside the scroll area so that you can snapback and continue where you left off.
I've never seen an app that didn't have that feature. Chrome included. I don't have powerpoint around to test at the moment. I've been using this feature since the 90s, and I'd miss it sorely if it were to be disappeared.
