Devices menu not shown in guest OS in VirtualBox (Ubuntu host, CentOS guest)

[mmasroorali]

I am running CentOS guest in Ubuntu VirtualBox host. In the guest OS, I can not find the Devices entry in the top menu bar.

There is a Help entry in the top menu bar, and that is it. There is no other entry.

I have already tried switching between scale-mode and no-scale-mode (Host+C key). Tweaking the View option in Settings of VirtualBox, without any success.