He was really asking about the menu bar as far as the Bookmarks menu, Opera 42 doesn't have a menu bar.
You can still download Opera 12, but it wasn't built for modern Linux systems. I mean, from the file dates 12.16 is over 3 years old. But it is still on the FTP server if you want it.
Opera 12.16 is ancient now. If you are not using some older distro or hardware you should try a more recent version. (Opera 12 was the last version for Linux based on their "Presto" engine, more recent versions are based on Chromium and as such require more RAM.)
Same thing happening to me! Don' know what to do? And I used use Opera in windows but last week I had to switch to Linux and Ubuntu operator but my all previous TAB in Opera browser in Windows all gone !!! I don't under stand why Opera does not save all TAB files under my account as I always been using signed up!