The [Preview] to scroll up or down to where I'm working: providing a real-time view of the design. As in, I click on an element, and the [Preview] would jump to where the element is.
The behaviour now is when you work on an element in a long design, you move over and scroll to where you are working so you may "preview" it.
It's easy enough to go to the top of the page by reloading the [Preview] or by adding my own [Jump to Top] button, but it is less so to keep scrolling up and down as I'm designing.