How to make menu stay on screen?

Question

After I choose a specific option from my menu, I want the menu to stay on screen and not to disappear. That means, in the code below, after I do something if the item id is R.id.undo, I want the menu to stay on screen.

public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
        case R.id.undo:
            // do something
            break;
        case R.id.clear:
            // do something
            break;
        default:
            return super.onOptionsItemSelected(item);
    }
    return true;
}