Description:
------------
This is related to bug #12860. The HTML tags are not stripped properly because of <?XML.

Bugfix #12860 fixes the problem of strip_tags parsing <?xml but not <?XML

I don't have control over the HTML I am stripping because it is from MS-Outlook generated HTML (ugh).

Regards, John Lim

Reproduce code:
---------------
<?php

# DOES NOT WORK
$s =<<< EOD
This text is shown <?XML:NAMESPACE PREFIX = ST1 /><b>This Text disappears</b>
EOD;

$s = strip_tags($s);
echo htmlspecialchars($s),"<hr>";


# WORKS

$s =<<< EOD
This text is shown <?xml:NAMESPACE PREFIX = ST1 /><b>This Text disappears</b>
EOD;

$s = strip_tags($s);
echo htmlspecialchars($s),"<br>";
?>

Expected result:
----------------
This text is shown This Text disappears
------
This text is shown This Text disappears

Actual result:
--------------
This text is shown 
------
This text is shown This Text disappears