I think it would be a great addition, if you could lock elements such as the header or footer to the top or bottom for instance. The way this could work is that you could label/define these elements as locked and then in the viewer mode they would stay at this position while scrolling (up or down). This would be useful for a better and more realistic feel of the final application or website (in case that function was considered). Something similar can be found in a tutorial of the pixate application explaining their scroll function. (http://www.pixate.com/education/video-tutorials/scroll-animations/)
You also have my vote for implementing scrolling in presentation mode :)
And within this feature, defining which area is scrollable –the rest would be fix.
I cannot user test how easy to find is an element if my prototype forces me to show all elements or work with collapsible elements :)
I do really need this feature. Especially, in my current project it comes hard to me to explain the intended scroll pattern. I would appreciate just showing the behavior instead of "Now figure out the nav would stick... and...".
Are there any current plans to that feature?