Eclipse Luna and plugin do not generate "import"

I have created a Vaadin7 with maven and imported in eclipse with Vaadin plugin.
Unfortunately now when I put a vaadin class eclipse do not insert “import” and if I use ctrl+space or ctrl+shift+O it does not list Vaadin packages as import source.

Please note that it does not work only for packages in “com.vaadin.ui”.
Application compiles and run.