code: @FXML
      void ignoreButtonOnAction(ActionEvent event) {
          if (!downloadThread.isAlive()) {
              // ignore this update
              this.hide();
              UpdateChecker.ignoreUpdate(updateInfo.toVersion);
          } else {
              // Cancel download
              UpdateChecker.cancelDownloadAndLaunch(this);
          }
      }
docs: Handler for Button[fx:id="cancelButton"] onAction