When Zbrush becomes the active window my mouse does not want to move. the clicks work, but it does not want to move!
I’ve checked zbrush settings, I havent changed anything.
Try uninstalling your wacom drivers and updating them. Reboot. Should work. 
Also, check to make sure winTab is running, and see if your tablet works in other programs correctly.
Did that, and it worked. That was odd, thank you very much!