Cannot change stored region

I tried:
1. select previously saved location and change x,y,w,h, then click save
2. select and delete previously saved location. then tap + to create a new region with the same name

When I close all OTR instances and reopen one, it still points to the old regions.

BTW, where does OTR store the saved regions? I might be able to directly change the config XMLs as a walk-around.