In early pre-release versions of RIA Services, the DomainDataSource control did not support filter descriptors for Enum properties. We were able to get this fixed for our V1.0 RC release though, and I mentioned that back in March. I said in that post that I'd follow up with details about our Enum support, but I never did (until now).
Someone actually called me out on this by commenting on the post. However, I thought the details of the comment were a bit humorous. Here's what I received in my inbox:
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