Just wondering why the intersect feature is greyed out while editing a multibody part in a assemby?

As soon as I edit the part out of the assembly I can use intersect. Doesn't seem to make any sense or reason especially when you can use split while editing a part in an assembly.

Maybe I need to turn a option on to see? (I can hope ROFL)

Saying that it's in the same league as inserting into a part while editing it in a assembly to make the single part a multi body. You can't do it unless you leave the assembly.