Use to divide the View window horizontally and work on two
parts of a program at the same time.
 
Use F6 and Shift+F6 to move between the windows:
  - F6 moves the cursor down through the windows.
  - Shift+F6 moves the cursor up.
 
To close a second View window, place your cursor in the
window that you want to keep active, and choose Split again.
 
To size the active window with a mouse, drag the window
boundary up or down.
 
To size the active window from the keyboard, use:
  - Alt+Plus(+)  to expand it one line.
  - Alt+Minus(-) to shrink it one line.
  - Ctrl+F10     to expand it to fill the screen, or return
                 it to its former size.