I just cut a small piece of 1/4" plywood to serve as a cover. For now, I am using rubberbands to hold the lid in place, until I can find a better solution.
This little organizer makes a compact and easy way to carry my tools and spooled materials items. My dubbing block fits nicely into the organizer. I drilled holes into a small wooden block, to serve as a holder for bobbins/tools. I've liked it so much, I have been using it on a regular basis for a couple weeks. Seems to do the trick.
Anyway, just sharing the idea, in hopes others find it helpful.