I am quite surprised how come nobody mention this but GlobalZOrder feature is so broken that I highly recommend others to not use it on the latest version.
I filed a bug a week ago and told about the basic issue in this forum as well. but now I understand the problem is much deeper then what I thought.
The problem in a nutshell -
Using SetGlobalZOrder break many of the features of cocos2dx such as :
TextureRender - when you try to capture a frame using ->visit the output is completely broken. you cant you TextureRender while using GlobalZOrder.
Using Scene transitions - any transitions that are done over a globalZOrder scene is broken.some elements are not affected by the transition. for example, a fadeout transition may still keep some of the nodes visible while tranisition applied.
Having said that, it seems that globalZOrder was added to the code but was not treated well with other features of cocos2dx. I highly suggest you warn people about it because now that I used it, it is a huge pain to go back.