I work with large projects. And I often need to move items around in my projects. However... while you're dragging an item in the Project Explorer, if the cursor is at the top or bottom of the visible area, the window does not scroll. This means that the item you're moving, and its destination, must both be visible at the same time in order to drag and drop it.
I regularly have to un-expand items in order to be able to simply move a file. This is time consuming and forces me to un-expand tree items that I would prefer to keep expanded.