$tl = $mw->Toplevel(-title=>"Stupid Program");
while (<DATA>){
process data
output to a text widget
}

my $cancel_btn=$action_frame->Button(-text=>"Cancel",
	   -command=> sub { 
	  		  $tl->withdraw
		  	  })->pack(-side =>'left', -expand=>1, -anchor => 'center');