Midi key editor causes Cubase to freeze


I have recently started using Cubase 8 Elements with Komplete Audio 6 interface. I record MIDI and everything works fine, it plays back ok etc. But when I double-click the track or go to Key Editor a blank white screen opens and Cubase crashes. I have to go to task manager to close it. I have tried disabling my preferences but the problems continues.

Thanks for any help.