Smarty

[jpbl]

on the line 54 of functions.html_options.php we can read:
$optgroup_html = '<optgroup label="' . htmlspecialchars($value) . '">' . "\n";

but this is a bug that cause a optgroup to not have his label correctly displayed. the line must be:
$optgroup_html = '<optgroup label="' . htmlspecialchars($key) . '">' . "\n";