code: public AbstractButton addButton(final String text, final Icon icon, final boolean toggleButton) {
          final AbstractButton button;
          if (toggleButton) {
              button = new JToggleButton(text, icon);
              button.addActionListener(_commonToggleButtonActionListener);
          } else {
              button = new JButton(text, icon);
          }
  
          addButton(button);
          return button;
      }
docs: Adds a button to this {@link ComboButton}
  
  @param text
  the text of the button
  @param icon
  the icon of the button
  @param toggleButton
  whether or not this button should be a toggle button (true) or
  a regular button (false)
  @return