It works for me: 
use Tk;

my $mw=new MainWindow;

my $toplevel;

my $toplevel_open=0;

my $status=$mw->Label(-text=>'Toplevel Closed :(')->pack;

$mw->repeat(1000,sub
{
    $status->configure(-text=>Exists($toplevel)?
        'Toplevel Open :)':'Toplevel Closed :(');
}
);

sub close_toplevel
{
    return if !Exists($toplevel);
    $toplevel->destroy;
}

$mw->Button(-text=>'Open Toplevel',-command=>
    sub {
        $toplevel=$mw->Toplevel();
    }
)->pack;

$mw->Button(-text=>'Close Toplevel',-command=>\&close_toplevel)->pack;

MainLoop;

[download]

In reply to Re^2: How can I find out whether a Tk Toplevel widget has been destroyed? by tkguifan
in thread How can I find out whether a Tk Toplevel widget has been destroyed? by tkguifan

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