Region Manager regions not showing when having only custom theme enabled

This is a very handy module, thanks.

I set it up the other day on a site where I had my custom theme and Garland enabled. It worked flawlessly right out of the box. Bravo.

I set it up today on another site where I had only the custom theme enabled. The admin theme was set to Garland.
I went to /admin/settings/region_manager/regions to set up the regions I wanted to use it on. The page was blank.

Aha! I thought, it must be because the admin theme was set to something other than my default theme.
So, I changed the admin them to the site's default theme. This had no effect.

I went to the theme settings page and enabled Garland but left my custom theme as the default one.
I went back to the /admin/settings/region_manager/regions page.

Now I have configurable regions for both the default theme and Garland.
It works well and it was not so hard to figure out, but for someone with no prior experience with the module this would be very unsettling.
Again, thanks for some really cool functionality.

You know what would be really cool is to have a way to sort disabled blocks within this interface. When the user creates blocks they get dropped randomly in the stack. A way of tagging blocks or sorting them alphabetically would be very nice and enhance it's usability.