Sorry I never replied here. I think when I posted this, I was having problems because the dark color makes it look like the components are already selected. Making the default background white (or even having a box that shows a checkmark when selected) would make it more obvious that one has to select something first (or it could say "please select components").
As to interface suggestions, the dark color in administration is a slight usability problem overall. After a recent update, I find that the background color on buttons for managing uploaded files is so dark, I can't read them without dragging with my mouse to reverse the color. (I know that's a separate issue, but related.) I know this can be changed by the user in the CSS, but something lighter as the default will be easier.
Thanks.