@Override
    public void actionPerformed(ActionEvent e) {
      final JFileChooser importPathChooser = new JFileChooser();
      int replaceTabs = JOptionPane.showConfirmDialog(rootPane, "Would you like to replace the current tabs?", "Replace Tabs", JOptionPane.YES_NO_CANCEL_OPTION);
      if (replaceTabs == 2) {
        // cancel selected
        return;
      }
      int returnVal = importPathChooser.showOpenDialog(rootPane);
      if (returnVal != JFileChooser.APPROVE_OPTION) {
        BurpExtender.getCallbacks().printOutput("Cannot open a file dialog for importing settings.");
        return;
      }
      File file = importPathChooser.getSelectedFile();
      String fileData = Utils.readFile(file);
      if (fileData.equals("")) {
        // file empty
        return;
      }
      if (replaceTabs == 1) {
        // do not replace current tabs
        BurpExtender.initializeFromSave(fileData, false);
      } else if (replaceTabs == 0) {
        // replace current tabs
        BurpExtender.getCallbacks().printOutput("Removing Tabs");
        BurpExtender.initializeFromSave(fileData, true);
      }
    }
Action listener for import settings menu
src/burp/Utils/AutoRepeaterMenu.java