Code:
dialog test {
  title "mIRC"
  size -1 -1 110 100
  option dbu

  menu "&File", 60
  item %menu1, 70

  item break, 180

  item "Save && &exit", 190, ok
  item "&Cancel", 200, cancel
}

on *:dialog:test:menu:70:{
  if ( %menu1 == on ) /set %menu1 off
  else /set %menu1 on
}

open dialog and click "File / (empty space)" then close dialog. open again and see "File/off" try again and changed to "on".
u mean this?