When calling an extension function that expects to handle DOM nodes, Saxon nodes are wrapped in a wrapper class that implements the DOM interface.
The implementation of the DOM Node interface is class NodeOverNodeInfo. The method isSupported(feature, version) on this class does not report feature information correctly, which may cause the calling application to believe that the DOM, for example, is not namespace aware.
Similarly, the class that implements the DOMImplementation interface is class DOMImplementationImpl, and this does not return anything useful from the hasFeature() method, causing similar problems.
A patch is being placed in Subversion, whose effect is to cause these methods to return true if the feature is "Core" or "XML" (case blind) and the version is null, "", "1.0", "2.0", or "3.0".