OK, we tested on all of our Windows 10 systems and the scroll bar works just fine, the mouse scroll wheel works just fine too. Do you have something installed on your system that alters the behavior of scroll bars?
We have had no reports from any other users of PM5 on Windows 10 with this same problem.
Do the arrow keys on your keyboard work for scrolling? They should scroll fast (depending on your keyboard key repeat rate setting.)
Another thing you could try is resetting your layout. Launch PM and then old down the Shift key while PM loads up. All docking panes, menus, toolbars should have their layouts restored to defaults.
-Kirk