Recently we announced Update to opentravel 2007b. Based on a review of the corresponding visual schemas by the opentravel team, an issue has been identified. This has been fixed and the visual schemas for opentravel schemas has been updated.
The issue identified is an interesting one. At issue is whether using NMTOKENS type as the base type for creating an enumerated restriction simpleType is correct or not. While the XML Schema specification does not explicitly prevent this, it certainly does not seem to be the right thing. Visual Schema code has been fixed to allow this type of schema definition.