sub variable {
    my $c = shift;
    my $oldvarref = $c->{'-variable'};
    my $oldval = $$oldvarref if $oldvarref;
    if(@_) {
	my $varref = shift;
        if ($oldvarref)
         {
	  $c->traceVdelete($oldvarref);
         }
	$c->{'-variable'} = $varref;
	$c->traceVariable($varref, 'w', sub { $c->value($_[1]) });
	$$varref = $oldval;
	_layoutRequest($c,2);
    }
    $oldval;
}
<\code>
<br>
Here is the fix<br>
<br>
<code>

sub variable {
    my $c = shift;
    my $oldvarref = "";
    my $oldval = "";
    if (defined($c->{'-variable'})) {
      $oldvarref = $c->{'-variable'};
      $oldval = $$oldvarref if $oldvarref;
    }

    if(@_) {
        my $varref = shift;
        $c->traceVdelete($oldvarref) 
             if (defined($oldvarref) and ($oldvarref ne ""));

        $c->{'-variable'} = $varref;
        $c->traceVariable($varref, 'w', sub { $c->value([1]) });

        $$varref = $oldval if (defined($oldval) and ($oldval ne ""));

        _layoutRequest($c,2);
    }
    return ($oldval) if (defined($oldval) and ($oldval ne ""));
}