This feature is present in newer versions of the program. As I can see in 6.1:
The button needs to be enabled under Tools>Customize>Toolbars.
On the left search for "Menubar" and add it to the list to the right.



That is for the standard UI.
There is also the new feature of "User interfaces" (that can be enabled as "experimental" under Tools>Options>Advanced>Enable experimental features - and then user interfaces can be switched from View>User interface), and (at least in some of the UI there) the option is present either as a button or as an option among the "Menu" options.
e.g.
with the "Tabbed" UI:

with the "Groupedbar" UI:
