code: def loadFilename( self, filename = '' ):
          
          if ( not (filename and isinstance(filename, basestring)) ):
              filename = QFileDialog.getOpenFileName( self,
                                                      'Open XDK File',
                                                      QDir.currentPath(),
                                                      'XDK Files (*.xdk)' )
              
              if type(filename) == tuple:
                  filename = nativestring(filename[0])
              
              if not filename:
                  return False
          
          if not (filename and os.path.exists(filename)):
              return False
          
          elif filename in self.loadedFilenames():
              return False
          
          self.loadFileRequested.emit(filename)
          self.setCursor(Qt.WaitCursor)
          
          return True
docs: Loads a new XDK file into the system.
          
          :param      filename | <str>
          
          :return     <bool> | success