You've got to be kidding.
Most of the basic UI elements from Win95 were not invented by Microsoft. They were cobbled together from a wide range of sources including CDE and other ancient window managers. A lot of the apparent missing prior art is MIA primarily because the author refused to really acknowledge the state of X before 1995.
The the first "clone" of Windows95 was nothing more than a theme for an existing window manager (fvwm).
A start menu is nothing more than an anchored app menu from any of the early window managers.