protected function flattenSelectorSingle($single)
{
$joined = array();
foreach ($single as $part) {
if (empty($joined) || !is_string($part) || preg_match('/[\\[.:#%]/', $part)) {
$joined[] = $part;
continue;
}
if (is_array(end($joined))) {
$joined[] = $part;
} else {
$joined[count($joined) - 1] .= $part;
}
}
return $joined;
}