only validate the current mug type in the tree on each change.
only validate the current mug type in the tree on each change.

will miss flagging some duplicate id problems, but makes changes
significantly faster.

esoergel/Vellum,johnhbenetech/Vellum,mwhite/Vellum,johnhbenetech/Vellum,mwhite/Vellum,johnhbenetech/Vellum,johnhbenetech/Vellum