code: private void buttonExportSettingsActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_buttonExportSettingsActionPerformed
      File file = DialogProviderManager.getInstance().getDialogProvider().msgSaveFileDialog(null, "exportSettings", "Export settings", lastExportedSettingsFile, true, new PropertiesFileFilter(), "Save");
      if (file != null) {
        lastExportedSettingsFile = file;
        if (!file.getName().toLowerCase(Locale.ENGLISH).endsWith(".properties")) {
          final Boolean addExt = DialogProviderManager.getInstance().getDialogProvider().msgConfirmYesNoCancel(null, "Add extension", "Add '.properties' extension?");
          if (addExt == null) {
            return;
          }
          if (addExt) {
            file = new File(file.getAbsolutePath() + ".properties");
          }
        }
  
        if (file.exists() && !DialogProviderManager.getInstance().getDialogProvider().msgConfirmOkCancel(null, "Override file", String.format("File %s exists, to override it?", file.getName()))) {
          return;
        }
  
        final PropertiesPreferences prefs = new PropertiesPreferences("NB MindMap plugin");
        final MindMapPanelConfig cfg = store(prefs, new MindMapPanelConfig(), false);
        cfg.saveTo(prefs);
        try {
          FileUtils.write(file, prefs.toString(), "UTF-8");
        } catch (final Exception ex) {
          LOGGER.error("Can't export settings", ex);
          DialogProviderManager.getInstance().getDialogProvider().msgError(null, "Can't export settings [" + ex.getMessage() + ']');
        }
      }
    }
docs: GEN-LAST:event_buttonResetSettingsActionPerformed