Have it create the box(es) when you access it, and destroy when done. That should curb normal memory use.
I tried this before, and it ended up being much easier to use popups.
Something that would be awesome: to define a combo or drop-down box and its values based on a var (say, "blue:green:red:black:purple"), setting the vars as you select.
(I've had a lot of pipe dreams lately :))