We have a number of custom attributes defined for our work items.
Some of those custom attributes are enumerations.

When I try to do a work item query using the custom attributes that
are enumerations no work items are displayed. However, queries on
the other custom attributes that are strings appear to work fine.

Is there something that needs to be done to get the enumeration types
to be queryable?

We have other custom attributes that are enumerations. They appear to
work properly when querying against them. It is only this particular
enum attribute that does not work.

I have looked at the process configuration source for the project and
there is no differences between the enums that work in the query and
the enums that do not work.

Is there anything else I can check to verify that the custom attribute
is setup properly.