It's the circular reference preventing garbage collection that would cause the leak. The same sort of leak that happens when you repeatedly create anonymous recursive subs like:
my $fact;
$fact = sub {
  my $n = shift;
  return $n if $n <= 1;
  return $n*fact($n-1);
}

[download]
Hmm, you're right, the other one would probably leak also if they both contain $button. (update: oops...looking at wrong thread since the OP didn't even have a circular reference in the example).

In reply to Re^3: what is difference between calling the function in Perl/Tk in the following ways by runrig
in thread what is difference between calling the function in Perl/Tk in the following ways by kiruthika.bkite

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