Hello Xiangchuan,
I followed your recipe and failed to crash afni. I suspect you have an older version with a bug that had been fixed. My test version was 2.51i (you can now check your version and find out which version is most recent with the Define Datamode-->Misc-->Version Check button).
You are the first person, to my knowledge, drawing ROI in the volume and watching them directly on the surface, pretty cool. I am working on implementing ROI drawing directly on the surface. I hope to make it available in the next few months.
cheers,
-ziad