code: public AbstractButton getButtonIn(Container container) {
  		Iterator it = buttonIterator();
  		while (it.hasNext()) {
  			AbstractButton button = (AbstractButton) it.next();
  			if (SwingUtilities.isDescendingFrom(button, container)) {
  				return button;
  			}
  		}
  		return null;
  	}
docs: Search for the first button of this command that is a child component of
  the given container.
  
  @param container the container to be searched.
  @return the {@link AbstractButton} representing this command that is
  embedded in the container or <code>null</code> if none was found.