Mr Tubbly

You can't see the result of the php code in the design window, only any pure html code you have used outside of the php. You can set up a Testing Server in the Manage Files option, and then use your usual Preview in Browser hotkey (default is F12), though this writes the file to the server, so make sure you're not overwriting an existing working php file with something that may not be tested yet !! Just make sure the URL Prefix under the server details is set correctly (eg http://www.yoursite.com/ and not http://www.yoursite.com/public_html/ which mine defaulted to).