I need help with an odd occurrence.  The model I am working on (not mine) has some shaded, and some transparent faces.  When viewing just the part it looks like this:

   HOWEVER, when during a spin, pan or zoom it immediately turns all the transparencies OFF:

    Only to display them again, once I stop moving things.

What is even stranger, is that as part of an assembly, the model transparencies stay on all the time, even when I moving things.  I haven't seen this behavior before, never happened on any of the parts/assemblies I have created.  Any one know what's going on and more importantly, how to fix/control this?

thanks in advance...