The Zend Framework is a non-visual library, but I asked whether it will handle visual controls in future. I was told that it will: Zend’s Zeev Suraski spoke about a forthcoming “Visual Component Model” along with “WYSIWYG tools” (though WYSIWYG is always a stretch with web applications).
Of course I was reminded of Delphi for PHP and its Visual Component Library. If Zend achieves its aim of making the Zend Framework something of a standard in the PHP community, that will be a blow for CodeGear’s product, unless somehow it could be re-worked to become a Zend Framework IDE. It seems to me that Zend’s framework has better chances than CodeGear’s. The documentation is incomparably better, and my early experiments suggest that the quality is good.
It is also interesting to see that the Zend Framework has built-in support for Google services.