Gitlab security update will be applied on February 23, between 8am and 9am, EST (UTC-05:00). This site may have intermittent delays during that time.
-Woverloaded-virtual complains because XdmfGrid's get* is hidden and made uncallable by the non virtual method of the same in the child class. Making the child virtual is problematic since the template parameter is not const in both.
This change ensures that both are visible to the user and prevents the compilation warning.