原来，有两个bug.一，它们没有覆盖CategoryOrderAttribute中的TypeID，二，它们没有使用TypeDescriptor.GetAttributes.我已经提交了两个错误……

Turns out there are two bugs in the source. One, they aren't overriding TypeID in CategoryOrderAttribute, and two, they aren't using TypeDescriptor.GetAttributes. I've submitted bugs for both...

https://github.com/xceedsoftware/wpftoolkit/issues/1522