Due to limitations of Zend Engine in PHP 4, PHP-GTK has some problematic issues. byref constructor (using %&new% instead of %new%, and not consistently at that) method invocation on properties (%$button->child->set_text()% will not work) memory deallocation (object destructors are never called) a couple of other minor ones Since it is such a large codebase and API, the documentation is lagging. We only have one active person working on the English version of documentation and a couple of translators for other languages. The applications have to be distributed with their source code, which may be beneficial or disadvantageous depending on your point of view. Some attemps have been made to encode the source, but the solution is not quite there yet. Finally, it would be nice to have a better way to install PHP-GTK applications on the desktop. There are some custom installers but a standard, professional one is still needed.