When viewing Storyline 2 and Studio '13 courses on a touchscreen device (iPad, iPhone, Android, etc.), use one finger to scroll through content in scrolling panels.
In HTML5 output, you can scroll anywhere in the scrolling panel. You don't necessarily have to use the scroll bar. (Mobile Safari doesn't show scroll bars until you begin scrolling.)
Articulate Mobile Player Output
In the Articulate Mobile Player app, you must use the scroll bar to navigate through scrolling panels.