In short, crud-ui seems to use v7-compatability widgetset, and the autocomplete-extension does not like this.
When my UI has
@Widgetset(“com.vaadin.v7.Vaadin7WidgetSet”)
the crud-ui addon works, but not autocomplete-extension. Removing the annotation gives the opposite result.
Running in Spring Boot 1.5.2 with vaadin4spring and autocomplete 0.2.1-SNAPSHOT from github.