Preview worked fine in Sierra on my early 2015 MacBook Pro. After upgrade to High Sierra, a "blur" effect appeared in changing pages, by which I mean a delay in rendering the page upon changing it with an arrow key. I just upgraded to Mojave hoping to have this corrected in its version of Preview, but the problem continues. Surely Apple must be aware of this annoying effect that has propagated into later OS's. Does anyone know of any effort by Apple to fix this? Does anyone have a workaround for the problem, other than switching to a different pdf viewer?