The DN_ENTERIDLE event is sent to the dialog callback function when the dialog enters the idle state.

Attention!

• This event has nothing to do with the timer. The dialog enters the idle state when there are no events in the system (no keystrokes, no mouse moves).

// while in Idle state let the computer calculate the next move
case DN_ENTERIDLE:
  Timer(hDlg);
  return 0;