setTitle doesn't work in fragment

I have a fragment where I try to change the title of the actionbar. This worked until i added setHasOptionsMenu(true) to the fragment. How can i solve this? Because I need the optionsmenu in the fragment.

In fragment

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    ((MainActivity)getActivity()).setActionBarTitle(getString(R.string.title_view_tree));
    setHasOptionsMenu(true);
    return inflater.inflate(R.layout.fragment_view_tree, container, false);
}

@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
    inflater.inflate(R.menu.menu_view_tree,menu);
    super.onCreateOptionsMenu(menu,inflater);

}

In MainActivity:

public void setActionBarTitle(String title) {
    getSupportActionBar().setTitle(title);
}

When I disable setHasOptionsMenu(true) by using // then the title of the actionbar changes correctly.

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