It's apparently empty. If I modify my original code to include the Dumper call as follows:

my $response = $mech->click({id => 'ProductSelect-option-color-solar-8
+568844557'});

print Dumper($response);
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The output is:

> ./www_mechanize_chrome_testcase.pl
$VAR1 = [];
Can't call method "is_success" on unblessed reference at ./www_mechani
+ze_chrome_testcase.pl line 26.
[download]