It is enchantrix. There are several ways to get to the configuration screen, right click on the minimap button, right click on the enchantrix button that pops out from the menu on the right side of the screen (along with bean counter, swatter, and several others), or type /enchantrix config.
You want to select automation and watch bags for disenchantable items. It doesn't do it automatically, a little pop up shows up and asks if you want to ignore (ignore always), no (ignore this session), or yes (de now).