Seems like Cubase Pro 8 still has problems when zooming in or out while the sequencer is in Play. Also I notice the VST Sylenth2s plugin window is tiny and to resize it I have to click on it but then it takes over the screen. I.E. it becomes normal size when clicked, but you cant see or access anything else until you " x" out. The window problem with Sylenth may be caused because I am running Cubase on Mac OS Yosemite? Anyway the crashing when zooming problem ALWAYS existed ever since Cubase 6.5 that I’ve noticed. 
I am having the same issue with Sylenth1. Also, is Cubase 8 Loading patches for Sylenth from older projects? My sylenth patches when loaded in C8 are all the init patch.