Editor Tree read order

Hi all;
Just a quick question regarding the Editor Tree. Is the read order from bottom to top or vice versa? I have noticed that Startup GKC(s) are added to the bottom of the tree by default so I am guessing from the bottom up. However, when zones overlap, the Zone highest in the tree is recognised and not that which is below.


To answer my own question, I tried an experiment and it appears to be from the top down. Could be wrong.