On the View Menu, click Full Screen (shortcut F), or click the 
button on the toolbar until it changes the browser orientation to full screen mode.
This allows you to switch between having either both the index and content panes or just the content pane taking up the full screen in Hyperview.
Note: Full screen mode does not imply that the Hyperview browser will take up the entire screen, merely that the Index Pane is hidden and the Content Pane takes up the entire area of the browser.
See also
- Adjusting the dividing line between panes
- Changing the pane orientation in the browser
- Switching focus to the other pane