■ Toggles display of include-file text in the active window
  on and off. Use this command only if your project contains
  an $INCLUDE metacommand.
 
■ A bullet (•) appears next to the command name on the View
  menu when the toggle is on.
  ┌─────────────────┐
  │ •Included Lines │
  └─────────────────┘
 
■ When Included Lines is on, the include-file text appears in
  high-intensity video following the $INCLUDE metacommand that
  names it. These displayed lines are read-only; you must load
  the include file into an code window to edit them.
 
■ To load the include file into the active window:
    • Choose Included File from the View menu
 
■ To load the include file into a new window:
    • Choose Code from the View menu
    • Select the include file you want to edit
    • Choose Edit in New