Issue: View container cannot be solved to a type

class vaStartup extends Application implements ParameterHandler, ViewContainer {

Issue: View container cannot be solved to a type

I’m running the latest auto-updated nightly builds
Is ViewContainer included in the core Vaadin .jar files, or am I missing external .jar file?
Fairly new to Vaadin, appreciate any feedback…

Are you sure it is not part of an addon like navigator 7 or app foundation ?
Can you paste here the corresponding import line ?