code: public void setupCellValueFactory() {
      navigationView.treeView.setCellFactory(param -> new TreeCell<Category>() {
        @Override
        protected void updateItem(Category category, boolean empty) {
          super.updateItem(category, empty);
          textProperty().unbind();
          if (empty || category == null) {
            setText(null);
            setGraphic(null);
          } else {
            textProperty().bind(category.descriptionProperty());
            setGraphic(category.getItemIcon());
          }
        }
      });
    }
docs: Makes the TreeItems' text update when the description of a Category changes (due to i18n).