Begins to load the item data for each tree level.
        
        :return     <bool> | success

def initialize( self ):
        """
        Begins to load the item data for each tree level.
        
        :return     <bool> | success
        """
        if ( self._initialized ):
            return True
        
        self._initialized = True
        
        # load the item's children
        model = self.model()
        signalsBlocked = False
        if ( model ):
            signalsBlocked = model.signalsBlocked()
            model.blockSignals(True)
            
        state = self.loadContext()
        
        if ( model ):
            model.blockSignals(signalsBlocked)
        
        return state