/** Update the GUI. */
 public void updateGUI() {
   defaultsPanel.updateGUI();
   euclidianPanel.updateGUI();
   spreadsheetPanel.updateGUI();
   casPanel.updateGUI();
   advancedPanel.updateGUI();
 }
  /** Update the labels of the components (e.g. if the language changed). */
  public void setLabels() {
    setTitle(app.getMenu("Settings"));

    closeButton.setText(app.getMenu("Close"));
    saveButton.setText(app.getMenu("Settings.Save"));

    tabbedPane.setTitleAt(TAB_DEFAULTS, app.getPlain("Defaults"));
    tabbedPane.setTitleAt(TAB_EUCLIDIAN, app.getPlain("DrawingPad"));
    tabbedPane.setTitleAt(TAB_SPREADSHEET, app.getPlain("Spreadsheet"));
    tabbedPane.setTitleAt(TAB_CAS, app.getMenu("CAS"));
    tabbedPane.setTitleAt(TAB_ADVANCED, app.getMenu("Advanced"));

    euclidianPanel.setLabels();
    defaultsPanel.setLabels();
    spreadsheetPanel.setLabels();
    casPanel.setLabels();
    advancedPanel.setLabels();
  }