Face extrusion

 From:  BurrMan
6880.1 
Hi Michael,
With regard to the new extrusion of faces, in this file, extruding the planar face, without "keep separate", give no preview of the extrusion. You have to actually select the distance for the extrusion to appear.

Surely it has something to do with the new "auto Boolean", but I'm not sure if it supposed to behave this way....