Problems with Caching

When I upgraded to 4.2.3 from 4.2.2 I no longer am able to see HTML before PHP code that takes a while to process. I made sure that I've set "output_buffering =off" but I still have this problem. When I hit the page with the following code on my server, it will wait 10 secs before it displays any of the HTML on the page. I want it to display the HTML at the top and then execute the code after the PHP block when the PHP has finished. This code worked in 4.2.2 but no longer. :-( Example code: <p id="hide">Working...</p> <?php sleep ( 10 ); ?> <p>&nbsp;</p> <p id="show" style="display:none;">DONE!</p> <script language="JavaScript"> <!-- show.style.display=''; hide.style.display='none'; //--> </script> Does anyone know what setting has caused this code to no longer work like it did in 4.2.2? Any input would be helpful. Thanks, Adam