inventor: how to remove an object from a set

[Matthias2000]

Good morning, I'm experiencing big problems in the elimination of an object in the 3d environment of inventor.
I attach image with selected the object I would like to remove but as you can see the option "elimina" is disabled.
Thank you.

Morning

 

[Catafratto]

You may be in a position representation other than main. . .