When I turn on X-ray (shading - x-ray) the objects in the scene some times disappear, like they're 100% transparent instead 50% or what ever they should be. Then the objects flicker between 50% and 100% transparency as I click and move around the scene. This is quite distracting I first ran into this problem after I downloaded Maya 8.5 PLE but this happens both in 7.0 and 8.5 Dos any one have any idea what could cause such a problem?