@Override
    public boolean onPrepareOptionsMenu(final Menu menu) {
        super.onPrepareOptionsMenu(menu);
        menu.findItem(R.id.menu_hint).setVisible(cache != null && StringUtils.isNotEmpty(cache.getHint()));

        final MenuItem ttsMenuItem = menu.findItem(R.id.menu_tts_toggle);
        ttsMenuItem.setVisible(cache != null);
        ToggleItemType.TOGGLE_SPEECH.toggleMenuItem(ttsMenuItem, SpeechService.isRunning());

        return true;
    }
refresh GUI elements which can be changed e.g. after a new configuration was issued (e.g. turning from portrait into landscape and vice versa
main/src/main/java/cgeo/geocaching/CompassActivity.java