Bad performance loading large ODDs

The ODD editor now takes a very long time to load some of the larger ODDs, e.g.

http://localhost:8080/exist/apps/tei-publisher/odd-editor.html?odd=tei_simplePrint.odd

The old, riot-based version did not have those issues, so it must be caused by heavy use of polymer webcomponents. Suspicion: paper-autocomplete might be the culprit.