// Begin of file.php
<font size="+1"><? echo "haha" ;?><b>HAHAH</b></font>
...........
// End of file.php

I found that the first tag after <? ?> couldn't be kept correctly. Say:
// Begin of my test script
$fp = fopen('file.php','r') ;
echo fgetss($fp,100,"<font><b>") ;
// End of my test script

The result would be <font size="+1">HAHAH</b></font>,
Seems that the first tag after <? ?>(<b> in this case) will lost.

My php.ini file is the same as php.ini-optimized.