I can place controls (GridView, DetailsView, etc.) from the toolbar onto my page, but I can't position them with mouse drag-and-drop. It's also impossible to move and position the toolbars and the Solution Explorer. Can you tell me how to fix it? Thanks.
(Drag-and-drop works in other programs on the same machine.)

 I had the same problem. You have to move the box (Solution Explorer, Data Explorer, etc.) around until transparent guides pop up and show you where to drop the box.