run with `spring run vaadin.groovy` (for http://stackoverflow.com/questions/30329121/vaadin-combobox-breaks-on-mulitiple-click-events#30329121)

vaadin.groovy

@Grapes([
@Grab('org.vaadin.spring:spring-boot-vaadin:0.0.5.RELEASE'),
@Grab('com.vaadin:vaadin-server:7.4.6'),
@Grab('com.vaadin:vaadin-client-compiled:7.4.6'),
@Grab('com.vaadin:vaadin-themes:7.4.6'),
])
import org.vaadin.spring.annotation.VaadinUI
import com.vaadin.server.VaadinRequest
import com.vaadin.ui.*

@VaadinUI
class MyUI extends UI {
        protected void init(VaadinRequest request) {
                setContent(new VerticalLayout().with{
			setMargin(true)
			addComponent(new ComboBox("my box").with{
				addItem("Alice")
				addItem("Bob")
				addItem("Charlie")
				it
			})
			it
		})
        }
}