Document groups can be dragged from any position and dropped at any position. They can also be dragged to and from the pinboard, in order to pin or unpin a group respectively. Groups can even be dragged from the bird's-eye view and dropped onto the regular document strip or onto the pinboard.
As related documents are grouped, drag-and-drop applies to those groups as a whole rather than to the individual documents.
While dragging, a small visual indicator shows where the document group will land if dropped now.