Does anyone know if screen yellowing is still an issue with the Retina iPad mini? Apple will be replacing my almost-year-old mini as the on/off switch stopped working. I was lucky enough to get a unit that didn't suffer too much from the yellowing issue last year, so I guess I was wondering if this was still a widespread problem or if they've mitigated the issue somehow in the year since the retina minis were first released. In searching around I didn't find much written about this in recent months so I wanted to see what people here thought. Either way I'll be looking it over very closely when I get my replacement unit...