[Chimera-users] question

Hi, Thank you for inventing the software, it rocks! By the way I have a question about viewing the 3D reconstruction image of a Virus like particle containing small nanoparticle cores. When I tried to increase the electron density in order to see the inside cores there always was a box showed up along with the nanoparticle. I want to know is there a way to remove the outside box? Here I attach an image to explain better what I mean. I appreciate you help. Thanks xinlei