Currently only LexReferenceSequenceView displays a full sequence for lexical relations sequence. Otherwise we could also manufacture ReferenceSequenceUi from ReferenceBaseUi.MakeUi(). But since only LexReferenceSequenceView (e.g. Calendar) is handling changing the sequence of items through the context menu, we'll wait till we really need it to come up with a solution that can "exclude self" from the list in moving calculations.