[fw-general] Zend_Filter_StripTags remove all the angle brackets <>

[Chou Ken]

Zend_Filter_StripTags remove all the angle brackets...
Is this a bug or a feature?

--- code ---
$string = 'a > b, a < b, a>b, a<b';

$filter = new Zend_Filter_StripTags();
var_dump($filter->filter($string));
var_dump(strip_tags($string));

--- output ---
string(12) "a  b, a b, a"
string(20) "a > b, a < b, a>b, a"