I was trying to find out how to add wireframes around a couple of regions I had added to a new subtheme of the Zen theme in D7 after I had successfully turned on wireframes for the standard regions. I began by trying to find out how wireframes were turned on for the sidebars by searching many files for region-sidebar-first (which can be found in the wireframes.css file but could not find any reference to that class in the source files I searched in both the subtheme and the Zen base theme.

On a lark I simply converted the statement in my info file "regions[triptych_1] = Triptych 1" to region-triptych-1 which I added to wireframes.css. Lo and behold, it worked! How, I have no idea, nor did I find any reference by Googling.

Could someone explain how this is accomplished?

Thanks.