Zend Server CE

Hi

I've moved on to Zend Server CE from Wamp. It's response is very fast on Windows 8 x64. I was having problem with Wamp server on Windows 8. There was a delay of 1 second on every action. I have one issue with Zend server. On install extension page, when I install or uninstall any module, the page refresh (i can see refresh icon go round on top) but download icon or delete icon do not change until I get out of the page and then go back. Is there any PHP extension missing on Zend server?

Thanks