Can't pull down quick settings panel?
Don't know if you still need a fix for this (it's been a few months since you posted), but anyway I had the same issue with not being able to open quick settings and also my M8 stopped displaying notifications. Not sure what triggered all that, but after performing a few dirty wipe re-flashes of my ROM, I finally did a clean wipe (not just system and caches but also data partition) and that fixed it. Having a google cloud backup made downloading everything a little easier, but I couldn't have avoided essentially wiping everything but my SD card and needing to reinstall all my apps.