The following video contains a short tour of each of the Document window views:
Click the tab with the name of the desired view.
By default, the upper portion of the window lets you choose any of 1-4 views, depending whether the sequence is nucleotide or protein. Views may include: Circular, Linear, Sequence, and Primer Design. The default view is Circular or Linear, depending on the sequence type. The lower portion of the window lets you choose any of 2-6 views, also depending on the sequence type. Views may include: Features, Primers, Comment, Minimap, Site Summary and History.
Use the mouse to drag and drop the view tab at the new location.
Use View > Split or View > Remove Split.