code: def navigator(self):
          
          if self._navigator is None:
              self._navigator = nav = XOrbColumnNavigator()
              self.lineEdit().setCompleter(None)
              
              # initialize settings
              nav.hide()
              nav.header().hide()
              nav.setWindowFlags(Qt.Popup)
              nav.setFocusPolicy(Qt.ClickFocus)
              nav.installEventFilter(self)
              nav.setVerticalScrollMode(nav.ScrollPerPixel)
              
              # create connections
              nav.itemClicked.connect(self.acceptColumn)
              self.lineEdit().textEdited.connect(self.showPopup)
              nav.schemaColumnChanged.connect(self.emitSchemaColumnChanged)
          
          return self._navigator
docs: Returns the navigator associated with this box.
          
          :return     <XOrbColumnNavigator>