Resource Property comb equation

I was just looking deeper into a part of my design. I can't work out how Quartus is deriving the Combout Equation for this

Labcell. See my picture.

The Equation says ( F & ( B ) )# ( !F ) which from my understanding says F AND B OR NOT F

From following the drawing, !Data F is used as the select for the mux. The input to the mux is

always B. It would seem that no matter what logic sense F was, the output would always

be B.

Can anyone shed any light on what Quartus is up to this time?

C