I see that the vsphere-wssdk-html sample has an example of a sub-menu, however it's commented out. Does this sample work for the specified version (6.5u1)?
Please review KB vSphere Client (HTML5) and vSphere Web Client 6.5 FAQ (2147929) that may assist on further clarifying this thread.
https://kb.vmware.com/s/article/2147929.
