I have  part that is not visible in either the hidden lines removed or hidden lines shown. I have had this happen in the past and all I had to do is update the model and it would appear, but with this part no matter what I do I can not get it be visible in either of above visibilities . It is visible however in wire frame, shaded with edges and shaded. Does anyone know what I can do get it to work in either hidden lines or hidden lines shown?