Updates this item to mark the item as loading.  This will create
        a QLabel with the loading ajax spinner to indicate that progress
        is occurring.

def startLoading(self):
        """
        Updates this item to mark the item as loading.  This will create
        a QLabel with the loading ajax spinner to indicate that progress
        is occurring.
        """
        if self._loading:
            return False
        
        tree = self.treeWidget()
        if not tree:
            return
        
        self._loading = True
        self.setText(0, '')
        
        # create the label for this item
        lbl = QtGui.QLabel(self.treeWidget())
        lbl.setMovie(XLoaderWidget.getMovie())
        lbl.setAlignment(QtCore.Qt.AlignCenter)
        tree.setItemWidget(self, 0, lbl)
        
        try:
            tree.loadStarted.emit(self)
        except AttributeError:
            pass
        
        return True