Deckmasters: Garfield vs. Finkel.. not on web site inventory?

Deckbox gets all of its data from the official Gatherer website.  The deckmasters set does exist, so you didn't buy a fake card or anything, but it isn't listed on Gatherer, so Deckbox doesn't show it.

I'm pretty sure that all of the data is just scraped from Gatherer.  There's nothing that can be done unless you want to petition Wizards to update with all editions of the cards, which probably won't happen at this time.

I'm still hoping that, at some point in time, Deckbox will get updated to pull information from http://magiccards.info instead/in addition to Gatherer, but I've received conflicting reports on the possibility of that happening, and there is definitely no timeline for that to occur.

The problem is that we don't know which cards belong to those undefined sets, and displaying that option for EVERY card doesn't make sense either.  For something like Giant Growth, that has twenty+ different editions, it probably doesn't matter much.  But to also list all of the unknown sets for something that is only in one set would just clog up the UI more than anything else.  For example:

Not to mention that it could easily lead to confusing situations where people can easily select editions of cards that don't even apply.