ok, so if containerPath is not supported, then can i get around it somehow? is putting javascript in the page my only remaining option?

i would say that the "current container ID" would be used only rarely. it was just an offhanded idea. it just seems like putting a link to that somewhere out of the way wouldn't be a terrible idea. you'd want to bury that a level or two deep in the menu, since it would only by used rarely. however, it's not at all high of my requested features list.