Code:
alias wallops {
  if (!$dialog(wallops)) dialog -dm wallops wallops
}

dialog wallops {
  title "Wallops Handler"
  size -1 -1 152 113
  option dbu
  list 1, 1 1 150 82, size hsbar vsbar
  edit "", 2, 1 85 112 10
  button "Send", 3, 116 85 34 11
  button "Close", 4, 44 99 50 10
}

on *:Wallops:*: {
  if ($dialog(wallops)) { 
    wallops
    did -a wallops 1 $1- by $nick 
  }
}

on *:Dialog:wallops:sclick:3: {
  if ($did($dname,2).text) { [color:red]![/color]wallops $did($dname,2).text }
}


/wallops - will open your dialog.
/!wallops - will send wallops messages.

Notice the exclamation mark, that needs to be there in order to cancel out your wallops alias.