Description:
------------
Combinations of unicode characters in brackets appear to match a completely incorrect character. We're using PHP 5.3.3 (cli). And I was able to reproduce the problem on a PHP regex test site.

http://www.pagecolumn.com/tool/pregtest.htm

Test script:
---------------
http://www.pagecolumn.com/tool/pregtest.htm

<?php
$ptn = "/[ÜŸ]/";
$str = "ø";
preg_match($ptn, $str, $matches);
print_r($matches);
?>

Should be the equivalent of the following, but is not

<?php
$ptn = "/Ü|Ÿ/";
$str = "ø";
preg_match($ptn, $str, $matches);
print_r($matches);
?>

Expected result:
----------------
I'd expect no matches.

Array
(
)

Actual result:
--------------
I get a match.

Array
(
    [0] => ø
)