Section 15.1.2 says you can have both dfdl:choiceBranchKey and a discriminator on a choice branch. But it doesn't clarify what the meaning of having both is. My assumption is that if you have both, the choice is resolved by the choiceDispatchKey/choiceBranchKey, so any discriminator would be about some surrounding point of uncertainty outside the choice. I wanted to confirm this is the intention. The alternative semantics would be that the discriminator is redundant, and so if it evaluates to true that means nothing at all since the choice branch has already been discriminated by the choiceDispatchKey/choiceBranchKey. If the discriminator evaluates to false, or errors when it evaluates, that would be a parse error that would cause the entire choice to fail. Comments? Mike Beckerle | OGF DFDL Workgroup Co-Chair | Tresys Technology | www.tresys.com Please note: Contributions to the DFDL Workgroup's email discussions are subject to the OGF Intellectual Property Policy <http://www.ogf.org/About/abt_policies.php>