btw, it’ll be a bit of time before I can code up extra theming support - adding support for the new features in OS X Lion is taking priority for the moment.
There are a few different types of label controls used, and the ones used in these locations only work properly on opaque backgrounds. I’d like to remove this restriction at some point, but there’s a considerable amount of work to do so while keeping sub-pixel antialiasing working correctly.
You can do this via adding a Widget.sublime-settings in your theme package, and overriding the colour scheme in there. Widget.sublime-settings accepts the same keys as Base File.sublime-settings, will override the settings in Base File.sublime-settings, and only applies to widgets. Take a look at the one in the Default package - it’s used to turn off things like line numbers and the line highlight, which don’t make sense for widgets to have.