Hello, I'm a newbie to Cocoa, just develop some little apps with C/C++ on Windows. I want to make a "simple" app on Cocoa. When the user specific XML file, the file nodes are represented "enduser viewable". I made an interface with some NSTextField. I made a subclass of NSDocument called "XMLFile" so i got "XMLFile.h" and "XMLFile.m" in my Xcode…