 
  Use when working on a multiple-module program to change its
initial execution location. During program development it is
common practice for each module to have test code as the
first executable statements.
 
┌─────── Set Main Module ──────┐
│ Choose new main module:      │
│ ▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒◄──Select a new main module
│ ▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒ │ here and choose <OK>.
│ ▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒ │
│                              │
│  <OK>                        │
└──────────────────────────────┘