Reordering fields doesn't work with delegating transformer implementations for the MultiValue field.
The MultiField component only implements the reordering itself, instead of delegating it to a common API for all multivalue transformers.
In worst case, if this cannot be done, then the reordering arrows should be hidden at least.
Updated in 2016-12-15
The final fix hides the up/down buttons if transfomerClass is DelegatingMultiValueFieldTransformer or its subclasses.