Why does the main OS menu bar disappear when I am in Safari?
Solution 1:
Strange I am having same issue when I log in. But changing desktops a few times solves the issue. So I think its a graphic bug
Solution 2:
I have also experienced this. What I found out was that it was as a result of dual display when I connected my MAC to my TV and used Safari in full-screen mode on the TV. I experienced Menu Bar disappear when I launch Safari after disconnecting from my TV. What I did to resolve the issue was to re-connect to TV and quit Safari while it was in full-screen mode (on the TV), and then relaunch the application.