I have a long TK program which I cannot include here. It precesses data and outputs results to a text widget. I am having a problem when cancelling my top level window, especially if the input data file is too long. The data processing keeps executing even though I had withdrawn the top level widget. Is this a common thing in Perl/Tk? Here is an abbreviation of my code: 
$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 => 'cente
+r');

[download]
I have to resort to killing the application in order to stop the process. Any ideas what I can do to resolve this issue? Thank you O great Saints!

In reply to $widget->withdraw by Anonymous Monk

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