SearchView in OptionsMenu not full width

Instead of creating a new layout I set the MaxWidth programmatically in onCreateOptionsMenu():

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.menu_search, menu);
    SearchView searchView = (SearchView)menu.findItem(R.id.menu_search).getActionView();
    searchView.setMaxWidth(Integer.MAX_VALUE);
    ....