I have been struggling with trying to re-topologize a model using the good old z-spheres but I keep running into a severe limitation that I cannot be able to overcome. I have googled hours but still cannot pinpoint the root cause. As I start re-topologizing the focus of the zsphere stays constrained to a random point in the mesh, it does not allow me to add/remove points/move them etc and my rotation of the model when I clicked outside of the mesh is locked, I noticed I can still rotate with the right mouse button and it seems to free it up. It happens more often when I try to rotate and hold shift to snap my canvas.
In my research I found this thread, http://www.maxforums.org/threads/help_please_zbrush/0001.aspx which is exactly my problem and here is the video :
https://www.youtube.com/watch?v=242S21SoGx0&feature=youtu.be
This is not my model but I am seeing the same exact behavior. You can see the behavior from 0-10 secs when you see him trying to rotate the model and a red line is projecting to his cursor. He is unable to rotate his model and ends up having to get out of edit mode.
Running zbrush 4r-7 on a core-i5 windows 10.